A bullet of mass 0.5 kg is moving horizontally with a speed of 50 m/s when it hits a block of mass 3 kg that is at rest on a horizontal surface with a coefficient of friction of 0.2. After the collision the bullet becomes embedded in the block. How much work is being dne by bullet?

Answer:

Một ô tô có khối lượng m=1000kg đang chạy với vận tốc 18km/h thì hãm phanh.​Biết lực hãm là 2000N. Tính quãng đường xe còn chạy thêm trước khi dừng ... Chiếu phương trình của định luật II Newtơn mà →F=m. ... chuyển động ta có F=m​a, suy ra gia tốc chuyển động của xe ( với F=2000N) ...

Explanation:

Answer:

Explanation:

The first thing we are asked to find is the Force experienced by the box. That is found in the formula:

F - f = ma where F is the force exerted by the box, f is the friction opposing the box, m is the mass, and a is the acceleration (NOT the same as the pull of gravity). But F can be rewritten in terms of the angle of inclination also:

[tex]wsin\theta-f=ma[/tex] where w is the weight of the box. We will use this version of the formula because it will help us answer the second question, which is to solve for a. Filling in:

First we need the weight of the box. Having the mass, we find the weight:

w = mg so

w = 25.14(10) so

w = 251.4 N (I am not paying any attention at all to the sig fig's here, since I noticed no one on this site does!) Now we have the weight. Filling that in:

251.4sin(30) - f = ma Before we go on to fill in for f, let's answer the first question. F = 251.4sin(30) so

F = 125.7   And in order to answer what a is equal to, we find f:

f = μ[tex]F_n[/tex] where Fn is the weight of the object.

f = .25(251.4) so

f = 62.85. Filling everything in now altogether to solve for a, the only missing value:

125.7 - 62.85 = 25.14a and

62.85 = 25.14a so

a = 2.5 m/s/s

Now we have to move on to another set of equations to answer the last part. The last part involves the y-dimension. In this dimension, what we know is that

a = -10 m/s/s

v₀ = 0 (it starts from rest)

Δx = -13.30 m (negative because the box falls this fr below the point fro which it started). Putting all that together in the equation for displacement:

Δx = v₀t + [tex]\frac{1}{2}at^2[/tex] and we are solving for time:

[tex]-13.30=0t+\frac{1}{2}(-10)t^2[/tex] and

[tex]t=\sqrt{\frac{2(-13.30)}{-10} }[/tex] so

t = 1.6 seconds to reach the bottom of the slope from 13.30 m high.

Answer:

  I = ⅓ m L²

Explanation:

They tell us to use the parallel axes theorem

         I = [tex]I_{cm}[/tex] + M d²

The moment of inertia of a rod with respect to the center of mass is

         I_{cm} = [tex]\frac{1}{12}[/tex]  m L²

the distance from the center of mass that coincides with its geometric center to the ends of the rod is

         d = L / 2

we substitute

       I =[tex]\frac{1}{12}[/tex]  m L² + m (L/2)²

       I = m L² (  [tex]\frac{1}{12} + \frac{1}{4}[/tex] )

       I = m L² ( [tex]\frac{1+3}{12}[/tex] )

       I = ⅓ m L²

Answer:

a) True. The battery obeys ohm's law, it is formed by an ideal source with a fixed internal resistance

c) True. Ohm's law is V = iR therefore voltage and current are proportional

Explanation:

In this problem let's analyze the load of the system, when a resistance is placed the current is 80 mA, if we place two resistors in parallel the voltage remains the same, but the current is divided between each resistance (bulb), therefore the current in the battery it must be 160 mA

Let's analyze the answers

a) True. The battery obeys ohm's law, it is formed by an ideal source with a fixed internal resistance

b) false

c) True. Ohm's law is V = iR therefore voltage and current are proportional

d) False

e) False. The current coming out of the battery is proportional to the load placed

Answer:

The range of the photon energies is between:

2.652 x 10⁻²⁵ J    to    4.973 x 10⁻²⁵ J

Explanation:

The energy of a photon is calculated using the following equation;

E = hf

where;

h is Planck's constant = 6.63 x 10⁻³⁴ Js

f is frequency of the photon

[tex]E = h \frac{c}{\lambda} \\\\where;\\\\\lambda \ is \ the \ wavelength\\\\c \ is \ the \ speed \ of \ light \ = 3\times 10^8 \ m/s\\\\When \ \lambda = 400 \ mm = 400 \ \times 10^{-3} \ m\\\\E = \frac{(6.63 \times 10^{-34})(3\times 10^8)}{400 \times 10^{-3}} \\\\E = 4.973 \times 10^{-25} \ J[/tex]

[tex]When \ \lambda = 750 \ mm = 750 \ \times 10^{-3} \ m\\\\E = \frac{(6.63 \times 10^{-34})(3\times 10^8)}{750 \times 10^{-3}} \\\\E = 2.652 \times 10^{-25} \ J[/tex]

The range of the photon energies is between:

2.652 x 10⁻²⁵ J    to    4.973 x 10⁻²⁵ J

Explanation:

Glasses or Contacts. You might not realize it, but if you wear glasses or contact lenses, this is light refraction at play. ...

Human Eyes. Human eyes have a lens. ...

Prism. ...

Pickle Jar. ...

Ice Crystals. ...

Glass. ...

Twinkling Stars. ...

Microscope or Telescope.

Answer:

the process of finding the age of fossils is called carbon dating because they use samples of carbon and compare it's characteristics to the samples of carbon from each set time

Answer:

= 0.257

Explanation:

Applied force on the safe by Bonnie and Clyde is F= 387 N + 341 N

= 728 N

Given safe slides with constant speed .So, force of friction =applied force

= 728 N

μ*normal force = 728 N

from this the safes coefficient of kinetic friction on the bank floor is

μ = 728 N / normal force

= 728 N / Mg

= 728 N / ( 289 * 9.8 )

= 0.257

Answer:

The final speed is 5.78 m/s.

Explanation:

mass, m = 375 g = 0.375 kg

initial velocity, u = 4 m/s

Distance, s = 2.5 m

Angle, A = 30 degree

Force, F = 1.5 N

let the final velocity is v.

Use the work energy theorem

Work done = change in kinetic energy

[tex]W= 0.5 m(v^2 - u^2)\\\\F s cos A= 0.5 m (v^2 - u^2)\\\\1.5\times 2.5\times cos30= 0.5\times 0.375\times (v^2 - 16)\\\\v = 5.78 m/s[/tex]

Answer:

Explanation:

Kinetic energy is at an absolute max when the potential energy is 0. At the ball's highest point, at its most absolute highest point, the velocity of the ball is 0, making KE = 0 and PE the only energy the ball has. So if this isn't a trick question, the wording is off.

Answer:

Attached below

Explanation:

The plot showing the potential as a function of distance from the center of the sphere is attached below

note : The Potential inside the sphere will remain constant as potential remains constant on surface and it start to decrease as 1/r

Answer:

The downwards acceleration is 3.53 m/s2.

Explanation:

Let the true weight is m g.

The reading of the balance, R = 0.64 mg

Let the acceleration is a.

As the apparent weight is less than the true weight so the elevator goes down wards with some acceleration.

Use Newton's second law

m g - R = m a

m g - 0.64 m g = m a

0.36 g = a

a = 3.53 m/s2

Answer: [tex]3.816\ m/s[/tex]

Explanation:

Given

Mass of Henry is 95 kg

Normal weight of Henry is [tex]mg=95\times 9.8=931\ N[/tex]

The scale reads the weight as 830 N for first 3.6 s i.e. less than the normal weight i.e. Elevator is moving downwards

Apparent weight is given by

[tex]\Rightarrow 830=m(g-a)\quad [a=\text{acceleration of elevator}]\\\Rightarrow 830=95(9.8-a)\\\Rightarrow 8.736=9.8-a\\\Rightarrow a=1.06\ m/s^2[/tex]

After 3.6 s weight becomes 930 N which is approximately equal to normal weight. It implies elevator starts moving with constant velocity i.e. no acceleration.

If elevator starts from rest, it velocity after 3.6 s is

[tex]v=u+at\\\Rightarrow v=0+1.06(3.6)\\\Rightarrow v=3.816\ m/s[/tex]

This velocity will remain continues as after 3.6 s, elevator starts moving with constant velocity.

Answer:

The acceleration of the object is -69.78 m/s²

Explanation:

Given;

postion of the particle:

[tex]x = 32t - 38\frac{t^3}{3} \\\\[/tex]

The velocity of the particle is calculated as the change in the position of the  particle with time;

[tex]v = \frac{dx}{dt} = 32 - 38t^2\\\\when \ the \ particle \ is \ at \ rest, \ v = 0\\\\32-38t^2 = 0\\\\38t^2 = 32\\\\t^2 = \frac{32}{38} \\\\t = \sqrt{\frac{32}{38} } \\\\t = 0.918 \ s[/tex]

Acceleration is the change in velocity with time;

[tex]a = \frac{dv}{dt} = -76t\\\\recall , \ t = 0.918 \ s\\\\a = -76(0.918)\\\\a = -69.78 \ m/s^2[/tex]

Answer: 90

Explanation: a=Fnet/M

=27/0.30

=90

the acceleration is 90

Answer:

The acceleration of the ball is 83.333ms2 [forward].

Explanation:

i hope it helps :)

Answer:

A) 3.367 × 10^(-6)

B) 2.97 × 10^(7) N/C

C) Upwards

Explanation:

We are given;

Mass of bee; m = 100 mg = 100 × 10^(-6) kg

Charge on bee;q=33 pC = 33 × 10^(-12)C

Electric field strength; E = 100 N/C

A) Formula for weight of bee; W = mg = 100 × 10^(-6) × 9.8 = 9.8 × 10^(-4) N

Electric force on Bee; F = qE = 33 × 10^(-12) × 100 = 33 × 10^(-10) N

ratio of the electric force on the bee to the bee's weight; F/W = (33 × 10^(-10))/(9.8 × 10^(-4)) = 3.367 × 10^(-6)

B) For the bee to be suspended in the air, it means the weight of the bee must be equal to the electric force. Thus;

mg = qE

100 × 10^(-6) × 9.8 = 33 × 10^(-12) × E

E = (100 × 10^(-6) × 9.8)/(33 × 10^(-12))

E = 2.97 × 10^(7) N/C

C) From Newton's law, sum of forces = 0.

Thus;

F_n + F + W = 0

Where F is the normal force.

Thus;

F_n = -(F + W)

F_n = - ((33 × 10^(-10)) + (9.8 × 10^(-4)))

F_n = -9.8 × 10^(-4) N

Thus, applied electric field is;

E_a = F_n/q = (-9.8 × 10^(-4))/(33 × 10^(-12)) = -2.97 × 10^(7) N/C

This is negative and so it means the direction will be opposite the Earth's electric filed which is upwards.

Answer:

wool and fibers

Explanation:

Answer:

The center of gravity of the tile is at the center of the tile:

Examining 1/2 of the tile, each mass  point will have an equal mass point

on the other side of the tile (considering a line thru the center of the tile)

with coordinates opposite and equal of the point being considered.

Each mass point will have an identical mass point on the opposite side of the tile, with coordinates opposite and equal to the point being analyzed, while looking at only half of the tile.

A hypothetical location where the gravitational force is said to appear to act is the human body's centre of gravity (COG). That is the location where the entire body's bulk appears to be concentrated[2]. The COG need not be located inside the actual boundaries of an object or a person because it is a hypothetical point. Imagine the thing balanced on one finger to get an idea of its COG (there are objective measurements).

The COG is positioned anatomically so that it is about anterior to the second sacral vertebra. The specific placement of the COG, however, continually shifts with each new posture of the torso and limbs since humans do not remain stable in the anatomical position. The dimensions of the body

The center of the gravity is at half of the length of tile.

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(a) 2.001N

(b) 2.001N

A sketch of the scenario has been attached to this response.

Since only the force vector F₁ is required, the only force shown in the sketch is F₁.

As shown in the sketch;

The x-component of the force vector F₁ = [tex]F_{x}[/tex]

The y-component of the force vector F₁ = [tex]F_{y}[/tex]

The magnitude of F₁ as given in the question = 2.83N

The angle that the force makes with respect to the x-axis = 45.0°

Using the trigonometric ratio, we see that;

(a) cos 45.0° = [tex]\frac{F_x}{F_1}[/tex]

=>  [tex]F_{x}[/tex] =  F₁ cos 45.0°

=> [tex]F_{x}[/tex] =  2.83 cos 45.0°

=> [tex]F_{x}[/tex] =  2.83 x 0.7071

=> [tex]F_{x}[/tex] =  2.001N

(b) Also;

sin 45.0° = [tex]\frac{F_y}{F_1}[/tex]

=>   [tex]F_{y}[/tex] =  F₁ sin 45.0°

=>  [tex]F_{y}[/tex] =  2.83 sin 45.0°

=>  [tex]F_{y}[/tex] =  2.83 x 0.7071

=>  [tex]F_{y}[/tex] =  2.001N

Therefore, the x-component and y-component of the force vector F₁ is 2.001N

The x and y component of vector F1 is mathematically given as

F_x =  2.001N

F_y=  2.001N

Question Parameters:

Generally, the equation for the x-component  is mathematically given as

x=Fsin\theta

Therefore

F_x =  F₁ cos 45.0°

F_x =  2.83 x 0.7071

F_x =  2.001N

For y component

x=Fcos\theta

F_y =  F₁ sin 45.0

F_y =  2.83 x 0.7071

F_y=  2.001N

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Answer:

The dipole always tries to align in the direction of electric field so that the net torque is zero.

Explanation:

When a dipole placed in an electric field at any arbitrary angle, it experiences a torque.

Let the dipole moment is p, electric field is E and the angle is A.  

The torque is given by

Torque = p E sin A

where, A is the angle between the electric field and dipole moment.

So, the dipole always tries to align in the direction of electric field so that the net torque is zero.

Answer:

θ = 12.5 rotations

Explanation:

The number of rotations can be found by using the second equation of motion:

[tex]\theta = \omega_i t + \frac{1}{2}\alpha t^2\\\\[/tex]

where,

[tex]\theta[/tex] = angular displacement = ?

ωi = initial angular speed = 0 rad/s

t = time = 5 s

α = angular acceleration = 2π rad/s²

Therefore,

[tex]\theta = (0\ rad/s)(5\ s)+\frac{1}{2}(2\pi\ rad/s^2)(5\ s)^2\\\\\theta = 78.54\ rad[/tex]

converting it to no. or rotations:

[tex]\theta = (78.54\ rad)(\frac{1\ rotation}{2\pi\ rad})[/tex]

θ = 12.5 rotations

Two connection methods are used for brushless DC motors. One method is to connect the coils in a loop as we compared it with the rotor winding of DC motors in Fig. 2.27. This method is called a Δ (delta) connection.

CORRECT ME IF IM WRONG!!

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Answer:

Example:Opening of a bottle cap by tool

when we hold a tool and open the bottle cap this is because , force x tool force .

The load arm is usually shorter than the effort arm in second order levers. Moving a large weight hence requires less effort. A force multiplier lever or effort multiplier lever is the name for this kind of lever. A boat's oars, for instance, can increase the force.

Second-order levers are devices with the input force farthest from the fulcrum and the output force on the same side of the fulcrum. A wheelbarrow is an excellent illustration of a second-order lever.

A second-order lever will have an output force greater than an input force, similar to first-order levers. The output journey, however, will be shorter than the input length. Both the input and output forces in this situation will move in the same direction.

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Answer:

the correct answer is D

Explanation:

In this exercise, the vectors are in the same west-east direction, so we can assume that the positive direction is east and perform the algebraic sum.

       R = δ + ε

where

       δ = 2.0 m

       ε = 7.0 m

the positive sign indicates that it is heading east

        R = 2.0 + 7.0

        R = 9.0 m

the direction is east

the correct answer is D

Explanation:

voltage is 50v and capacitance is 30c what is the charge

q=1500c

Answer:

F = 7.72 N

Explanation:

The magnetic force on the charge can be given by the following formula:

[tex]F = qvB Sin\theta[/tex]

where,

F = magnetic force = ?

q = magnitude of charge = 9.7 C

v = speed of charge = 0.75 m/s

B = magnetic field = 1.5 T

θ = angle = 45°

Therefore,

[tex]F = (9.7\ C)(0.75\ m/s)(1.5\ T)Sin45^{o}[/tex]

F = 7.72 N

Answer:

I’ll try my best!

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Answer:

an unconscious needs rooted in childhood are the foundation of psychoanalytic theory.

Explanation:

Answer:

By measure the effective length and the time period of the pendulum.

Explanation:

Let the student take the oscillating pendulum at the planet.

He measure the time period of the pendulum  by using the stop watch or the ordinary watch.

Then measure the effective length of the pendulum which is the distance between the center of gravity of the bob and the point of suspension of the pendulum.

Now, use the formula of the time period of the pendulum,

[tex]T =2\pi\sqrt\frac{L}{g}[/tex]

Here, L is the effective length of the pendulum, g is the acceleration due to gravity at the planet and T is time period of the pendulum.  

By rearranging the terms, we get

[tex]T =2\pi\sqrt\frac{L}{g}\\\\T^{2}=4\pi^2\times\frac{L}{g}\\\\g =\frac{4\pi^2L}{T^2}[/tex]

Here, by substituting the values of L and T, the student get the value of acceleration due to gravity at that planet.