1. What types of natural phenomena could serve as time standards?

Answers

Answer 1
In practice, something that follows a very predictable pattern can be used as a time standard. This include things like radioactive decay, planetary orbit, and the speed of light, among others.
Answer 2

Answer:

The movement of Sun and moon

Explanation:

When the sun rise.it is am and when it sets .it is pm.


Related Questions

(will give brainliest to whoever answers first and explains reasoning) A 10kg object is spun around in a circle with a centripetal acceleration of 3.5m/s^2. What is the centripetal force acting on the object?

Answers

Answer:

35 N

Explanation:

F = ma

centripetal force = 10(3.5) = 35 N

What is the only difference between the reactant and product side of a chemical reaction?

Answers

Answer:

Products is the result. Reactants produce the result

Explanation:

,,

A motorist is driving at 15 m/s when she sees that a traffic light 315m ahead has just turned red. She knows that this light stay red for 25 s, and she wants to be 20 m from the ligt when it turns green again. Taht way, she will still be able to stop if the light stays red longer than expected. She applies the brake gradually such that her acceleration is ax(t)= c + bt, where c and b are constant. Assume she starts with a constant speed at the origin.

Find the values of c a b and any other unknown constants in order to answer the following questions.

1. Given the motorist's acceleration as a function of time, what are her position and velocity fucntions? - Do not use numbers for any constant here. Only derive the position and velocity functions.

2. What is her speed as she reaches the light?

Answers

Answer:

1)   x = x₀ + vot - ½ c t² - 1/6 bt³,    v = v₀ - ct - ½ b t²

2)   v₁ = 5.25 m/s,         v₂ = -8 m/s

Explanation:

1) For this exercise, the relationship of the body is not constant, so you must use the definition of speed and position to find them.

acceleration is

           a = c + bt

a) the relationship between velocity and acceleration

           a = [tex]\frac{dv}{dt}[/tex]

           dv = -a dt

The negative sign is because the acceleration is contrary to the speed to stop the vehicle.

we integrate

           ∫ dv = - ∫ a dt

           ∫ dv = -∫ (c + bt) dt

            v = -c t - ½ b t²

This must be valued from the lower limit, the velocity is vo, up to the upper limit, the velocity is v for time t

             v - v₀ = -c (t-0) - ½ b (t²-0)

             v = v₀ - ct - ½ b t²

b) the velocity of the body is

             v = [tex]\frac{dx}{dt}[/tex]

             dx = v dt

we replace and integrate

              ∫ dx = ∫ (v₀ - c t - ½ bt²) dt

              x-x₀ = v₀ t - ½ c t² - ½ b ⅓ t³

Evaluations from the lower limit the body is at x₀ for t = 0 and the upper limit the body is x = x for t = t

           x - x₀ = v₀ (t-0) - ½ c (t²-0) + [tex]\frac{1}{6}[/tex]  (t³ -0)

 

           x = x₀ + vot - ½ c t² - 1/6 bt³

2) The speed when you reach the traffic light

Let's write the data that indicates, the initial velocity is vo = 15 m / s, the initial position is xo = 315m, let's use the initial values ​​to find the constants.

       t = 25 s x = 20

we substitute

          20 = 315 + 15 25 - ½ c 25² - 1/6 b 25³

         0 = 295 + 375 - 312.5 c - 2604.16 b

         670 = 312.5 c + 2604.16 b

we simplify

         2.144 = c + 8.33 b

Now let's use the equation for velocity,

        v = v₀ - ct - ½ b t²

        v = 15 - c 25 - ½ b 25²

        v = 15 - 25 c - 312.5 b

               

let's write our two equations

        2.144 = c + 8.33 b

        v = 15 - 25 c - 312.5 b

Let's examine our equations, we have two equations and three unknowns (b, c, v) for which the system cannot be solved without another equation, in the statement it is not clear, but the most common condition is that if the semaphore does not change, it follows with this acceleration (constant) to a stop

               a = c + b 25

from the first equation

              c = 8.33 / 2.144 b

              C = 3.885 b

we substitute in the other two

            v = 15 - 25 (3.885 b) - 312.5 b

            v = 15 - 409.6 b

final acelearation

            a = 28.885 b

           

let's use the cinematic equation

               [tex]v_{f}^2[/tex]= v² - 2 a x

                0 = v² - 2a 20

               0 = v² - (28.885b) 40

               v² = 1155.4 b

we write the system of equations

               v = 15 - 409.6 b

               v² = 1155.4 b

resolve

              v²= 1155.4 ( [tex]\frac{15 -v }{409.6}[/tex] )

              v² = 2.8 ( 15 -v)

              v² + 2.8 v - 42.3 = 0

              v=  [ -2.8 ±[tex]\sqrt {2.8^2 + 4 \ 42.3) }[/tex] ]/2 = [-2.8 ± 13.3]/2

              v₁ = 5.25 m/s

              v₂ = -8 m/s

A 41.0-kg crate, starting from rest, is pulled across level floor with a constant horizontal force of 135 N. For the first 15.0 m the floor is essentially frictionless, whereas for the next 12.0 m the coefficient of kinetic friction is 0.320. (a) Calculate the work done by all the forces acting on the crate, during the entire 27.0 m path. (b) Calculate the total work done by all the forces. (c) Calculate the final speed of the crate after being pulled these 27.0 m.

Answers

Answer:

Explanation:

From the information given;

mass of the crate m = 41 kg

constant horizontal force = 135 N

where;

[tex]s_1 = 15.0 \ m \\ \\ s_2 = 12.0 \ m[/tex]

coefficient of kinetic friction [tex]u_k[/tex] = 0.28

a)

To start with the work done by the applied force [tex](W_f)[/tex]

[tex]W_F = F\times (s_1 +s_2) \times cos(0) \ J[/tex]

[tex]W_F = 135 \times (12 +15) \times cos(0) \ J \\ \\ W_F = (135 \times 37 )J \\ \\ W_F =4995 \ J[/tex]

Work done by friction:

[tex]W_{ff} = -\mu\_k\times m \times g \times s_2 \\ \\ W_{ff} = -0.320 \times 41 \times 9.81 \times 12 \ J \\ \\ W_{ff} = -1544.49 \ J[/tex]

Work done  by gravity:

[tex]W_g = mg \times (s_1+s_2) \times cos (90)} \ J \\ \\ W_g = 0 \ j[/tex]

Work done by normal force;

[tex]W_n = N \times (s_1 + s_2) \times cos (90) \ J[/tex]

[tex]W_n = 0 \ J[/tex]

b)

total work by all forces:

[tex]W = F \times (s_1 + s_2) + \mu_k \times m \times g \times s_2 \times 180 \\ \\ W = 135 \times (15+12) \ J - 0.320 \times 41 \times 9.81 \times 12[/tex]

W = 2100.5  J

c) By applying the work-energy theorem;

total work done = ΔK.E

[tex]W = \dfrac{1}{2}\times m \times (v^2 - u^2)[/tex]

[tex]2100.5 = 0.5 \times 41 \times v^2[/tex]

[tex]v^2 = \dfrac{2100.5}{ 0.5 \times 41 }[/tex]

[tex]v^2 = 102.46 \\ \\ v = \sqrt{102.46} \\ \\ \mathbf{v = 10.1 \ m/s}[/tex]

A physicist drives through a stop light. When he is pulled over, he tells the police officer that the Doppler shift made the red light of wavelength 635 nm appear green to him, with a wavelength of 550 nm. The police officer writes out a traffic citation for speeding. How fast was the physicist traveling, according to his own testimony

Answers

Answer:

Explanation:

[tex]\lambda[/tex] = Observed wavelength = 550 nm

[tex]\lambda'[/tex] = Actual wavelength = 635 nm

c = Speed of light = [tex]3\times 10^8\ \text{m/s}[/tex]

v = Velocity of the physicist

Doppler shift is given by

[tex]f=\sqrt{\dfrac{c+v}{c-v}}f'\\\Rightarrow \dfrac{c}{\lambda}=\sqrt{\dfrac{c+v}{c-v}}\dfrac{c}{\lambda'}\\\Rightarrow \dfrac{\lambda'^2}{\lambda^2}=\dfrac{c+v}{c-v}\\\Rightarrow \dfrac{\lambda'^2}{\lambda^2}=\dfrac{1+\dfrac{v}{c}}{1-\dfrac{v}{c}}\\\Rightarrow \dfrac{\lambda'^2}{\lambda^2}(1-\dfrac{v}{c})=1+\dfrac{v}{c}\\\Rightarrow \dfrac{\lambda'^2}{\lambda^2}(1-\dfrac{v}{c})=1+\dfrac{v}{c}\\\Rightarrow \dfrac{\lambda'^2}{\lambda^2}-1=\dfrac{v}{c}(1+\dfrac{\lambda'^2}{\lambda^2})\\\Rightarrow v=\dfrac{c(\dfrac{\lambda'^2}{\lambda^2}-1)}{1+\dfrac{\lambda'^2}{\lambda^2}}[/tex]

[tex]\Rightarrow v=\dfrac{3\times 10^8\times (\dfrac{635^2}{550^2}-1)}{1+\dfrac{635^2}{550^2}}\\\Rightarrow v=42817669.77\ \text{m/s}[/tex]

The physicist was traveling at a velocity of [tex]42817669.77\ \text{m/s}[/tex].

If we always drop the balls from 1-m
height in each trial, what type of variable
is this in this experiment?
Constant Variable
Dependent Variable
Independent Variable

Answers

Answer:

height

weight of ball

time of ball falling

Describe how spatial awareness during physical activity impacts student performance

Answers

I uploaded the answer to a file hosting. Here's link:

tinyurl.com/wpazsebu

Spatial awareness may impact student performance (even physical performance) because spatial understanding is fundamental for visual processing.

Spatial awareness refers to the understanding of a person (in this case a student) and of the relationships between different objects within a specific space.

It has been shown that spatial awareness can affect performance in mathematics, punctuation spelling, etc.

An example of spatial awareness includes the visualization of different objects from different perspectives.

In conclusion, spatial awareness may impact student performance (even physical performance) because spatial understanding is fundamental for visual processing.

Learn more in:

https://brainly.com/question/15279294

NEED HELP ASAP, ILL GIVE YOU BRAINLIEST IF CORRECT (30POINTS)


Drag each label to the correct location on the image. Each label can be used more than once.

Identify the parts of the barred spiral galaxy.

SPIRAL ARM, NUCLEUS, BAR


NOTE I JUST FILLED IN THE SPOTS FOR YOU TO SEE, THEY ARE NOT CORRECT

Answers

Answer:

the bar is the top and bottem. the nucleas in the middle and the Spiral arm is the last space

Explanation:

Answer:

look pkch

Explanation:

Which of the following have frequencies greater than orange light Your answer:
radio waves
purple light
ultraviolet rays
red light
green light
gamma rays
microwaves
infrared rays

Answers

Answer:

Gamma Rays have the highest frequencies

Explanation:

This is because Gamma rays have the highest energies, the shortest wavelengths, and the highest frequencies compared to the other light frequency. Radio waves, on the other hand, have the lowest energies, longest wavelengths, and lowest frequencies of any type of EM radiation which means the answer has to be gamma rays. Brainly Please!!!! Here are screenshots that may help

Investigator Daniels is working on the scene of a suspected arson on a rainy evening. The site of the fire was a mechanic's garage, so there are plenty of accelerants
on the scene. According to the owner of the garage, there had been an argument with a customer the day before about his motorcycle. All the employees left by
6:00 pm. The office was unharmed but there is much damage in the mechanic's bay area and toolboxes. The flames look to have been most concentrated around a
bucket that the owner says was filled with oily rags. She is trying to sift through the evidence and find the relevant facts of the case so far. In order to effectively
Identify the relevant facts, Investigator Daniels creates a word bank. Which word would not fit into her word bank?
Argument
Rainy
Olly rags
Toolboxes

Answers

Answer:

Rainy

Explanation:

It is the only one that has nothing to do with the case

Find the momentum of a 15 kg object traveling at 7 m/s

What is the momentum
What is the velocity
What is the mass

What equation did you use to solve?

Answers

Find the momentum of a 15 kg object traveling at 7 m/s.

The momentum of an object is found by using the following formula:

[tex]\displaystyle p=mv[/tex]

P is the momentum and is measured in kg · m/sm is the mass and is measured in kgv is the velocity and is measured in m/s

In this question, the object is 15 kg and is travelling at 7 m/s. That means the mass is 15 kg and the velocity is 7 m/s.

Since all the needed variables are found, substitute it into the equation:

[tex]\displaystyle p=mv \rightarrow p=15 \times 7[/tex]

Multiply:

[tex]\displaystyle p=105\ kg \times m/s[/tex]

__________________________________________________________

What is the momentum? 105 kg · m/s

What is the velocity? 7 m/s

What is the mass? 15 kg

What equation did you use to solve? p = mv

__________________________________________________________

When6-2 He He-6 undergoes beta decay, the daughter is?​

Answers

Answer: The daughter is named Susie.

Explanation: LIL SUSIE!!!

                      HUH? DIDN'T UNDERSTAND THE QUESTION!

                                        HAVE A GREAT DAY!!!!!

Answer:6/3 Li

Explanation:

I’m not sure what the person under me is talking about but yeah

ASAP Even though the force exerted on each object in a collision is the same strength, if the objects have different masses, their will be different. * O changes in velocity O amount of force O speed and direction​

Answers

Answer:

it should be changes in velocity

Explanation:

I hope this helps!

Which of the following best describes gravitational potential energy,
O The energy stored in an object when you lift it,
O The energy stored in an object due to its chemical structure,
The energy of an object in motion.
The energy stored in an object due to its electric charges.

Answers

The energy stored in an object when you lift it,

1
Select the correct answer.
Which type of energy is thermal energy a form of?
A
chemical energy
B.
kinetic energy
C. magnetic energy
D. potential energy
Reset
Next

Answers

Answer:

B. kinetic energy

Explanation:

Thermal energy (It’s a low form of energy ) is a form of kinetic energy as it is produced as a result of motion of particles either if they vibrate at their position or they move along longer paths.

Mechanical energy is the most concentrated form of energy.
a. true
b. false

Answers

( False )Nuclear energy is the most concentrated form of energy.

Adding resistors in series changes the total resistance of a circuit by
(5 points)
O increasing the resistance
O decreasing the resistance
o it does not affect the resistance
o decreasing the resistance if the value of the resistor added is less than the
greatest resistor in the circuit

Answers

Answer:

Increasing the resistance

Explanation:

Answer: A

Explanation:

increasing the resistance

Calculate the kinetic energy of an 80,000 kg airplane that is flying with a velocity of 167 m/s.

Answers

Answer:

1115560000 J

Explanation:

1/2 * 80,000 * 167^2 m/s = 1115560000 J

a boy standing by a lake sees a fish in the pond and tries to thrust a spear into it he will success or not​ explain with reason​

Answers

He will probably not succeed. Light does not travel as quickly through water than it does air, so the light will bend around the fish to make it look like it is in one place when really it is in another. I studied this a long time ago so I am kind of rusty on it, sorry. I really hope this helps. Have a great day!

He will not probably success to thrust a spear into the  fish in the pond because when light travels from water to air , it bends due to refractive property of light.

What is refraction of light?

Refraction is the bending of a wave as it travels through different media. The two materials' different densities are what lead to the bending.

Refraction is defined as "the change in a wave's direction as it passes through a medium."

Although light refraction is one of the most frequently seen phenomena, refraction can also occur with sound and water waves. We can use optical tools like lenses, prisms, and magnifying glasses thanks to refraction. We can focus light on our retina because of the refraction of light, which is another benefit.

When light travels from water to air , it bends due to refractive property of light. So, he e will not probably success to thrust a spear into the  fish.

Learn more about refraction  here:

https://brainly.com/question/14760207

#SPJ2

(5 Points)
a) At ground level, the pressure of the helium in a balloon is 1x105
Pa. The volume occupied by the helium is 9.6m The balloon is
released and it rises quickly through the atmosphere. Calculate
the pressure of the helium when it occupies a volume of 12m3.
(3 Marks)
b) A box is 15m below the surface of the sea. The density of sea-
water is 1020 kg/m.
Calculate the pressure on the box due to the sea-water.
(2 Marks)

Answers

Answer:

1. [tex]P_{2}[/tex] = 8 x [tex]10^{4}[/tex] Pa

2. P = 1.5 x [tex]10^{5}[/tex] N/[tex]m^{2}[/tex]

Explanation:

1. From Boyles' law;

[tex]P_{1}[/tex][tex]V_{1}[/tex] = [tex]P_{2}[/tex][tex]V_{2}[/tex]

[tex]P_{1}[/tex] = 1 x [tex]10^{5}[/tex] Pa

[tex]V_{1}[/tex] = 9.6 [tex]m^{3}[/tex]

[tex]V_{2}[/tex] = 12 [tex]m^{3}[/tex]

Thus,

1 x [tex]10^{5}[/tex] x 9.6 =  [tex]P_{2}[/tex] x 12

 [tex]P_{2}[/tex] = [tex]\frac{100000 x 9.6}{12}[/tex]

     = 80000

[tex]P_{2}[/tex] = 8 x [tex]10^{4}[/tex] Pa

2. Pressure, P = ρhg

where: ρ is the density of the fluid, h is the height/ depth and g is the acceleration due to gravity (9.8 m/[tex]s^{2}[/tex]).

Thus,

P = 1020 x 15 x 9.8

  = 149940

P = 1.5 x [tex]10^{5}[/tex] N/[tex]m^{2}[/tex]

A uniform-density 7 kg disk of radius 0.20 m is mounted on a nearly frictionless axle. Initially it is not spinning. A string is wrapped tightly around the disk, and you pull on the string with a constant force of 42 N through a distance of 0.9 m. Now what is the angular speed

Answers

Answer:

The angular speed is 23.24 rad/s.

Explanation:

Given;

mass of the disk, m = 7 kg

radius of the disk, r = 0.2 m

applied force, F = 42 N

distance moved by disk, d = 0.9 m

The torque experienced by the disk is calculated as follows;

τ = F x d = I x α

where;

I is the moment of inertia of the disk = ¹/₂mr²

α is the angular acceleration

F x r = ¹/₂mr² x α

The angular acceleration is calculated as;

[tex]\alpha = \frac{2Fr}{mr^2} \\\\\ \alpha = \frac{2F}{mr}\\\\\alpha = \frac{2 \times 42 }{7 \times 0.2} \\\\\alpha = 60 \ rad/s^2[/tex]

The angular speed is determined by applying the following kinematic equation;

[tex]\omega _f^2 = \omega_i ^2 + 2\alpha \theta[/tex]

initial angular speed, ωi = 0

angular distance, θ = d/r = 0.9/0.2 = 4.5 rad

[tex]\omega _f^2 = 2\alpha \theta\\\\\omega _f = \sqrt{2\alpha \theta} \\\\\omega _f = \sqrt{2 \times 60 \times 4.5} \\\\\omega _f = 23.24 \ rad/s[/tex]

Therefore, the angular speed is 23.24 rad/s.

A reaction occurs when a compound breaks down. This reaction has one reactant and two or more products. Energy, as from a battery, is usually needed to break the compound apart.

Answers

Answer:

decomposition

Explanation:

how can we minimise the use of plastic​

Answers

Answer:

recyclable toothbrushes, cardboard or metal straws, cardboard gallons instead of plastic, use glass and reusable cups

Explanation:

Select the correct answer.
Which graph shows the correct relationship between kinetic energy and speed?

Answers

Answer:

c

Explanation:

It's c the last one u see

A 416 kg merry-go-round in the shape of a horizontal disk with a radius of 1.7 m is set in motion by wrapping a rope about the rim of the disk and pulling on the rope. How large a torque would have to be exerted to bring the merry-go-round from rest to an angular speed of 3.7 rad/s in 2.9 s

Answers

Answer:

The torque exerted on the merry-go-round is 766.95 Nm

Explanation:

Given;

mass of the merry-go-round, m = 416 kg

radius of the disk, r = 1.7 m

angular speed of the merry-go-round, ω = 3.7 rad/s

time of motion, t = 2.9 s

The torque exerted on the merry-go-round is calculated as;

[tex]\tau = Fr= I\alpha\\\\\tau = (\frac{1}{2} m r^2)(\frac{\omega }{t} )\\\\\tau = (\frac{1}{2} \times 416 \times 1.7^2)( \frac{3.7}{2.9} )\\\\\tau = 766.95 \ Nm[/tex]

Therefore, the torque exerted on the merry-go-round is 766.95 Nm

which causes magnets to stick to metal

Answers

Answer:

Steel

Explanation:

Steel is a metal that magnets stick to because iron can be found inside steel

Answer:Magnets stick to any metal that contains iron, cobalt or nickel.

Explanation:Iron is found in steel, so steel attracts a magnet and sticks to it. Stainless steel, however, does not attract a magnet.

A potter's wheel is rotating around a vertical axis through its center at a frequency of 2.0 rev/srev/s . The wheel can be considered a uniform disk of mass 4.5 kgkg and diameter 0.30 mm . The potter then throws a 2.8-kgkg chunk of clay, approximately shaped as a flat disk of radius 8.0 cmcm , onto the center of the rotating wheel. Part A What is the frequency of the wheel after the clay sticks to it

Answers

Answer:1.7 rev/s

Explanation:

Given

Frequency of wheel [tex]N_1=2\ rev/s[/tex]

angular speed [tex]\omega_1=2\pi N_1=4\pi\ rad/s[/tex]

mass of wheel [tex]m_1=4.5\ kg[/tex]

diameter of wheel [tex]d_1=0.30\ m=30\ cm[/tex]

radius of wheel [tex]r_1=\frac{d_1}{2}=\frac{30}{2}=15\ cm[/tex]

mass of clay [tex]m_2=2.8\ kg[/tex]

the radius of the chunk of clay [tex]r_2=8\ cm[/tex]

Moment of inertia of Wheel

[tex]I_1=\dfrac{m_1r_1^2}{2}=\dfrac{4.5\times 15^2}{2}\ kg-cm^2[/tex]

Combined moment of inertia of wheel and clay chunk

[tex]I_2=\dfrac{m_1r_1^2}{2}+\dfrac{m_2r_2^2}{2}=\dfrac{4.5\times 15^2}{2}+\dfrac{2.8\times 8^2}{2}\ kg-cm^2[/tex]

Conserving angular momentum

[tex]\Rightarrow I_1\omega_1=I_2\omega_2\\\Rightarrow \dfrac{4.5\times 15^2}{2}\cdot 4\pi=(\dfrac{4.5\times 15^2}{2}+\dfrac{2.8\times 8^2}{2})\omega_2\\\\\Rightarrow \omega _2=\dfrac{4\pi }{1+\dfrac{2.8}{4.5}\times (\dfrac{8}{15})^2}=\dfrac{4\pi}{1+0.1769}=0.849\times 4\pi[/tex]

Common frequency of wheel and chunk of clay is

[tex]\Rightarrow N_2=\dfrac{4\pi \times 0.849}{2\pi}=1.698\approx 1.7\ rev/s[/tex]

A 38.0 kg box initially at rest is pushed 4.00 m along a rough, horizontal floor with a constant applied horizontal force of 130 N. If the coefficient of friction between box and floor is 0.300, find the following. (a) the work done by the applied force J (b) the increase in internal energy in the box-floor system due to friction J (c) the work done by the normal force J (d) the work done by the gravitational force J (e) the change in kinetic energy of the box J (f) the final speed of the box m/s

Answers

Answer:

a)  Wapp = 520 N

b)  ΔUf = 447 N

c) Wn = 0

d) Wg = 0

e) ΔK = 73 J

f) v = 1.96 m/s

Explanation:

a)

Applying the definition of work, as the dot product between the applied force and the displacement, since both are parallel each other, the work done on the box by the applied force can be written as follows:

       [tex]W_{app} = F_{app} * \Delta X = 130 N * 4.0 m = 520 N (1)[/tex]

b)

The change in the internal energy due to the friction, is numerically equal to the work done by the force of friction.This work is just the product of the kinetic force of friction, times the displacement, times the cosine of the angle between them.As the friction force opposes to the displacement, we can find the work done by this force as follows:

       [tex]W_{ffr} = F_{fr} * \Delta X * cos (180) (2)[/tex]

The kinetic force of friction, can be expressed as the product of the kinetic coefficient of friction times the normal force.If the surface is level, this normal force is equal to the weight of the object, so we can write (2), as follows:

       [tex]W_{ffr} = F_{fr} * \Delta X * cos (180) = -\mu_{k} * m* g* \Delta X = \\ -0.300*38.0kg9.8 m/s2*4.0m = -447 J (3)[/tex]

So, the increase in the internal energy in the box-floor system due to the friction, is -Wffr = 447 J

c)

Since the normal force (by definition) is normal to the surface, and the displacement is parallel to the surface, no work is done by the normal force.

d)

Since the surface is level, the displacement is parallel to it, and the gravitational force is always downward, we conclude that no work is done by the gravitational force either.

e)

The work-energy theorem says that the net work done on the object, must be equal to the change in kinetic energy.We have two forces causing net work, the applied force, and the friction force.So the change in kinetic energy must be equal to the sum of the work done by both forces, that we found in a) and b).So, we can write the following expression:

        [tex]\Delta K = W_{app} + W_{ffr} = 520 J - 447 J = 73 J (4)[/tex]

f)

Since the object starts at rest, the change in kinetic energy that we got  in e) is just the value of the final kinetic energy.So, replacing in (4), we finally get:

       [tex]\Delta K = 73 J = \frac{1}{2}*m*v^{2} (5)[/tex]

Solving for v:[tex]v_{f} = \sqrt{\frac{2*\Delta K}{m} } = \sqrt{\frac{2*73J}{38.0kg}} = 1.96 m/s (6)[/tex]

a) The work done by the applied force   [tex]W_{AP}=520\ J[/tex]

b) The change in the internal energy [tex]\Delta U=447\ J[/tex]

c) Work done by normal force  [tex]W_n=0[/tex]

d) Work done by gravitation   [tex]W_g=0[/tex]  

e) The change in KE will be [tex]\Delta KE=73\ J[/tex]

f) The final speed v = 1.96 m/s

What will be the work done?

The work done on any object can be defined as the force applied on the object and its displacement due the effect of the force.

If the object achieve movement due to the work then the energy in the object will be kinetic energy.

If the object attains some height  against the gravity then the energy in the object will be potential energy.

Now it is given in the question that

The horizontal force   [tex]F_h=130\N[/tex]

mass of the object  m= 38 kg

Coefficient of friction [tex]\mu=0.3[/tex]

Displacement of the object [tex]\delta x=4\ m[/tex]

(a) The work done will be

[tex]W=F_h\tines \Delta x[/tex]

[tex]W=130\times 4=520\ J[/tex]

(b) The increase in the internal energy

The increase in the internal energy of the box is due to the energy generated by the force of friction so

[tex]W_f=F_f\times \Delta x\times Cos(180)[/tex]

here  [tex]F_f[/tex] is the frictional force and is given as

[tex]\mu=\dfrac{F_f}{R}[/tex]

Here R is the normal reaction and its value will be weight of the box in opposite direction.

[tex]\mu=\dfrac{F_f}{-mg}[/tex]

[tex]F_f=-mg\times \mu[/tex]

[tex]W_f=F_f\times \Delta x\times Cos180=-mg\times\mu \times cos180[/tex]

[tex]W_f=-38\times 9.81\times 0.3\times4=-447\J\ J[/tex]

(c) The work done by the normal force will be zero because the displacement is horizontal against the normal work so the work done will be zero.

(d) The work done by the gravitational force will also be zero. Because the displacement is horizontal and the gravitational force acts downward.

(e) The change in the KE of the box.

The change in the KE of the box will be the net energy of the box so from the work energy theorem the net energy will be

[tex]\Delta KE =W_{AP}-W_f=520-447=73\ J[/tex]

(f) The speed of the box

The KE of the box will be

[tex]KE=\dfrac{1}{2} mv^2[/tex]

[tex]v=\sqrt{ \dfrac{2\times KE}{m}[/tex]

[tex]v=\sqrt{\dfrac{2\times73}{38} }=1.96\ \dfrac{m}{s}[/tex]

Thus

a) The work done by the applied force   [tex]W_{AP}=520\ J[/tex]

b) The change in the internal energy [tex]\Delta U=447\ J[/tex]

c) Work done by normal force  [tex]W_n=0[/tex]

d) Work done by gravitation   [tex]W_g=0[/tex]  

e) The change in KE will be [tex]\Delta KE=73\ J[/tex]

f) The final speed v = 1.96 m/s

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Calculate the first and second order angles for light of wavelength 400. nm and 700. nm of the grating contains 1.00 x 104 lines/cm.

Answers

Answer:

[tex]23.58^{\circ}[/tex] and [tex]53.13^{\circ}[/tex]

[tex]44.43^{\circ}[/tex], second order does not exist

Explanation:

n = Number of lines grating = [tex]1\times10^4\ \text{Lines/cm}[/tex]

[tex]\lambda[/tex] = Wavelength

m = Order

Distance between slits is given by

[tex]d=\dfrac{1}{n}\\\Rightarrow d=\dfrac{1}{1\times 10^4}\\\Rightarrow d=10^{-6}\ \text{m}[/tex]

[tex]\lambda=400\ \text{nm}[/tex]

m = 1

We have the relation

[tex]d\sin\theta=m\lambda\\\Rightarrow \theta=\sin^{-1}\dfrac{m\lambda}{d}\\\Rightarrow \theta=\sin^{-1}\dfrac{1\times 400\times 10^{-9}}{10^{-6}}\\\Rightarrow \theta=23.58^{\circ}[/tex]

m = 2

[tex]\theta=\sin^{-1}\dfrac{2\times 400\times 10^{-9}}{10^{-6}}\\\Rightarrow \theta=53.13^{\circ}[/tex]

The first and second order angles for light of wavelength 400 nm are [tex]23.58^{\circ}[/tex] and [tex]53.13^{\circ}[/tex].

[tex]\lambda=700\ \text{nm}[/tex]

m = 1

[tex]\theta=\sin^{-1}\dfrac{1\times 700\times 10^{-9}}{10^{-6}}\\\Rightarrow \theta=44.43^{\circ}[/tex]

m = 2

[tex]\theta=\sin^{-1}\dfrac{2\times 700\times 10^{-9}}{10^{-6}}[/tex]

Here [tex]\dfrac{2\times 700\times 10^{-9}}{10^{-6}}=1.4>1[/tex] so there is no second order angle for this case.

The first order angle for light of wavelength 700 nm are [tex]44.43^{\circ}[/tex].

Second order angle does not exist.

What type of weather would a continental Polar air mass bring

Answers

Answer:

Continental polar ( cp):

Explanation:

Cold and dry, originating from high latitudes, typically as air flowing out of the polar highs. This air mass often brings the rattleing cold, dry and clear weather on a perfect winter day and also dry and warm weather on a pleasant day in summer.

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