Answer:
Acceleration: -9.8 m/s^2
Velocity: -28.2 m/s
Displacement: 143.1 m
Explanation:
The acceleration of gravity for any object close to earth is approximately -9.8 m/s^2.
Now, to find the velocity after 9 seconds, we can use a kinematics formula, where x is the final velocity:
Final Velocity = Initial Velocity + Acceleration * Time
x = 60 + -9.8*9
x = 60 - 88.2
x = -28.2
The velocity is -28.2 m/s.
Lastly, to find the displacement, we can use another kinematics formula, where y is the displacement:
Displacement = (Final Velocity + Initial Velocity)/2 * Time
y = (-28.2 + 60)/2 * 9
y = 143.1
The displacement is 143.1 meters.
One particle, of mass m , moves with a speed v in the x-direction, and another particle, of mass 2 m , moves with a speed v/2 in the y-direction. what is the velocity of the center of mass of these two particles?
Given :
One particle, of mass m , moves with a speed v in the x-direction, and another particle, of mass 2 m , moves with a speed v/2 in the y-direction.
To Find :
The velocity of the center of mass of these two particles.
Solution :
Speed of mass m, [tex]v\ \hat i[/tex].
Speed of mass 2m , [tex]\dfrac{v}{2}\ \hat{j}[/tex] .
Speed of center of mass is given by :
[tex]v_{cm }= \dfrac{m\times( v\ \hat{i}) + 2m \times \dfrac{v}{2}\ \hat{j} }{m + 2m}\\\\v_{cm}=\dfrac{v( \hat{i} + \hat{j})}{3}[/tex]
Hence, this is the required solution.
The velocity of the center of mass of these two particles will be [tex]\rm v_{cm}= \frac{v(\vec i+\vec j)}{3}[/tex]
What is velocity?The change of displacement with regards to time is defined as speed. Speed is a scalar quantity. It is a time-based component. Its unit is m/sec.
The given data in the problem is
[tex]\rm V_i[/tex] is the speed of mass m
[tex]\rm \frac{v}{2} \hat j[/tex] is the speed of mass 2m
Speed of the center of mass will be;
[tex]\rm v_{cm}=\frac{m \times (v \hat i)+2m \times \frac{v}{2}\hat j }{m+2m} \\\\ \rm v_{cm}= \frac{v(\vec i+\vec j)}{3}[/tex]
Hence the velocity of the center of mass of these two particles will be [tex]\rm v_{cm}= \frac{v(\vec i+\vec j)}{3}[/tex].
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a car accelerates from a standstill to 60 km/hr in 10 seconds. what is the cars acceleration
As you get older your muscles grow.
True
True
False
Answer:
f
Explanation:
Answer:
yeah but if you get in your 30s you start to lose muscles
A refrigerator draws 4.5 A of current while operating on a 120-V power line. If the refrigerator runs 50% of the time and electric power costs $0.15/kWh, how much does it cost to run this refrigerator for a 30-day month
Answer:
$ 29.16
Explanation:
The following data were obtained from the question:
Current (I) = 4.5 A
Voltage (V) = 120 V
Time (t) = 30 days
1 KWh = $ 0.15
Cost for 30 days =.?
From the question given above, we were told that the refrigerator runs 50% of the time.
Thus, the time of operation of the refrigerator will be:
Time (t) = 30 × 50% = 30 × 50/100
= 15 days.
Next, we shall convert 15 days to hours. This can be obtained as follow:
1 day = 24 h
15 days = 15 days × 24 h / 1 day
15 days = 360 h
Next, we shall determine the energy consumed in KWh This can be obtained as follow:
Current (I) = 4.5 A
Voltage (V) = 120 V
Time (t) = 360 h
Energy (E) =?
E = ivt
E = 4.5 × 120 × 360
E = 194400 Wh
Next, we shall convert 194400 Wh to KWh. This can be obtained as follow:
1000 Wh = 1 KWh
Therefore,
194400 Wh = 194400 Wh × 1 KWh/ 1000 Wh
194400 Wh = 194.4 KWh
Thus the energy consumed is 194.4 KWh
Finally, we shall determine the cost of energy consumed. This can be obtained as follow:
From the question given above,
1 KWh cost $ 0.15
Therefore, 194.4 KWh will cost = 194.4 KWh × $ 0.15 = $ 29.16
Therefore, the cost of running the refrigerator for 30 days is $ 29.16
Write the expression for the frequency of a mass m on a spring moving horizontally. Suppose that k is the spring constant. Express your answer in terms of some or all of the variables k, m, g.
Answer:
[tex]f=1/2\pi *\sqrt{k/m}[/tex]
Explanation:
This is the equation of the frequency of a spring in the horizontal direction.
if 49 jules of work is done when a 7 newton wagon of cheeseburgers is pulled, how far does it move?
how is atmospheric and water pressure different?
Answer: Electric charges
Explanation: Atmospheric pressure isn't able to crush you because it doesn't result from weight or surface area. Atmospheric pressure, also known as weather patterns, results from escaping atmospheric gases coming together and creating electric charges. Oceanic pressure in caused from high compression of the upper layers of the water, producing thousands of tons of liquid weight crushing the bottom layer. This is how they are different forms of pressure.
If, instead, the mass remained the same as the original problem, but the spring was replaced by one with a spring constant that was four times as large, the period would be:__________
Answer:
T = [tex]1/2\pi \sqrt (k/m) \\[/tex] so period of mass spring system becomes 2 times w.r.t original problem.
Explanation:
[tex]T =1/2\pi \sqrt(k/m)\\[/tex] so when k = 1 is replaced by 4 it means it becomes
k" = 4k
[tex]T' = 1/2\pi \sqrt(k'/m)\\T' = 1/2\pi \sqrt(4k/m)\\T' = 2(1/2\pi\sqrt(k/m)\\)\\T' = 2T[/tex]
The velocity of a passenger relative to a boat is -vpb. The velocity of the boat relative to the river it is moving on is vbr. The velocity of the river to the shore is vrs. What is the velocity of the passenger relative to the shore
Answer:
vps = vbr + vrs - vpb
Explanation:
If the passenger were at rest, his speed relative to the shore will be identical to the boat's, as follows:vps = vbr + vrsAs he is moving in a direction opposite to the boat's, his velocity relative to the shore must be less than if he were at rest, in the same quantity that he was moving opposite to the boat, as follows:vps = vbr+ vrs -vpbA force of 25 newtons moves a box a distance of 4 meters in 5 seconds. The work done on the box is_ No, and the power is_Nm/s
Explanation:
workdone = force x distance
workdone= 25 x 4
workdone = 100 joules ( the unit for workdone is joules or Nm )
POWER = workdone/ time
power = 100/5
power = 20 watts ( the unit for power is watts or Nm/s )
Arocket with an initial velocity of 20 m/s another engine that gives it an acceleration of 4 m/s ^ 2 over 10 secondsHow far did the rocket travel during this time
Answer:
50m
Explanation:
Given parameters:
Initial velocity = 20m/s
Acceleration = 4m/s²
Time = 10s
Unknown:
Distance traveled by the rocket = ?
Solution:
To solve this problem use the expression below;
v² = u² + 2as
v is the final velocity
u is the initial velocity
a is the acceleration
s is the distance
final velocity = 0
Insert the parameters and solve;
0² = 20² + 2 x 4 x s
-400 = 8s
s = 50m
Disregard the negative sign because distance cannot be negative.
11. A 100-W incandescent light bulb has a cylindrical tungsten filament 30.0 cm long, 0.40 mm in diameter, and with an emissivity of 0.26. (a) What is the temperature of the filament
Answer:
T = 556K
Explanation:
For this exercise let's use Stefan's law
P = σ A e T⁴
where the stafan-Boltzmann constant is 5,670 10⁻⁸ W / m² K⁴.
In this case the area of a circular cylinder is
A = π r²
the radius is
r = d / 2 = 0.150 m
A = π (0,150)²
A = 7.0685 10⁻² m²
let's clear
T⁴ = P /σ A e
T⁴ = 100 / (5.670 10⁻⁸ 7.0685 10⁻² 0.26)
T⁴ = 9.5966 10¹⁰ = 959.66 10⁸
T = 5.56 102 K
T = 556K
The temperature of the filament is 366.3 K
Using the equation for radiated power, P
P = σεAT⁴ where σ = Stefan-Boltzmann constant = 5.67 × 10⁻⁸ W/m²K⁴, ε = emissivity = 0.26, A = area of cylindrical tungsten filament = πDh (since it radiates through its sides)where D = diameter of tungsten filament = 0.40 mm = 0.4 × 10⁻³ m and h = length of tungsten filament = 30.0 cm = 0.3 m and T = temperature of tungsten filament.
Since we require the temperature of the filament, making T subject of the formula, we have
T = ⁴√(P/σεA)
T = ⁴√(P/σεπDh)
Since P = 100 W, substituting the values of the variables into the equation, we have
T = ⁴√(P/σεπDh)
T = ⁴√(100 W/5.67 × 10⁻⁸ W/m²K⁴× 0.26 × π× 0.4 × 10⁻³ m × 0.3 m)
T = ⁴√(100 W/0.5558 W/K⁴ × 10⁻⁸)
T = ⁴√179.93 × 10⁸ K⁴)
T = 3.663 × 10² K
T = 366.3 K
So, the temperature of the filament is 366.3 K
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A force of 29.4 N is required to pull a 100 kg ice block at constant speed along an ice surface. Find the coefficient of kinetic friction for ice on ice.
Answer:
The value is [tex]\mu_k = 0.03[/tex]
Explanation:
From the question we are told that
The force applied on the ice is [tex]F = 29.4 N[/tex]
The mass of the ice block is [tex]m = 100 \ kg[/tex]
Generally for the ice block to move at constant speed , the force applied on it must be equal to the kinetic frictional force which is mathematically represented as
[tex]F_F = m* g * \mu_k[/tex]
=> [tex]F = F_F = m* g * \mu_k[/tex]
=> [tex]29.4 = 100 * 9.8 * \mu_k[/tex]
=> [tex]\mu_k = 0.03[/tex]
Assume that the left side of your heart creates a pressure of 118 mm Hg by exerting a force directly on the blood over an effective area of 16.0 cm^2. What force does it exert to accomplish?
Answer:
251.5 x 10⁻⁴ N
Explanation:
Pressure = Force / surface area
Force = pressure x area
pressure = 118 mm of Hg
= .118 x 13.6 x 9.8 N / m²
= 15.72 N / m ²
area = 16 x 10⁻⁴ m²
Force = 15.72 x 16 x 10⁻⁴
= 251.5 x 10⁻⁴ N .
A 100-turn coil has a radius of 7.50 cm and a resistance of 50.0 W. At what rate must a perpendicular magnetic field change to produce a current of 5.00 A in the coil
Answer:
dB / dt = -141.47 T / s
Explanation:
For this exercise let's use Faraday's law to calculate the induced electromotive force
E = - N dФ / dt
the magnetic flux is
Ф = B. A
in this case the direction of the field and the normal to area are parallel so the scalar product is reduced to the algebraic product
Ф = B A
we substitute
E = - N A dB / dt
the area of the loop is
A = π r²
we substitute
E = - N π r² dB / dt
in the exercise indicate that the resistance of the coil is R = 50.0 Ω,
E = i R
we substitute
i R = -N π r² dB / dt
dB / dT = - i R / N π r²
let's calculate
dB / dt = - 5.00 50.0 / (100 π 0.075²)
dB / dt = -141.47 T / s
A box with a mass of 5.8 kg is lifted from the garage floor and placed on a shelf. If the box gains 145 J of
potential energy, how high is the self?
Answer:
2.27
Explanation:
Potential energy =mgh so from there u can substitute the values
A quarter is tossed up from the roof of a skyscraper and hits the sidewalk below. Which of the following graphs best shows the velocity v vv of the quarter from when it is tossed up until it reaches the ground?
Answer:
pic
Explanation:
The graph which best shows the velocity v of the quarter from when it is tossed up until it reaches the ground is attached in the answer.
What is velocity?
Velocity is the time rate of change of displacement. The displacement and velocity both are vector quantities. They represent magnitude and direction as well.
A quarter is tossed up from the roof of a skyscraper and hits the sidewalk below.
The velocity will decrease with the time linearly.
The graph which best shows the velocity v of the quarter from when it is tossed up until it reaches the ground is attached in the solution.
Learn more about velocity.
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How does the formation of ice in the freezing compartment of a
refrigerator demonstrate the particulate nature of matter?
A. As the particle energy of matter decreases, the motion of the atoms in a
given space decreases
B. As the particle energy of matter decreases, the motion of atoms in a given
space increases
C. As the particle energy of matter increases, the motion of atoms in a given
space decreases
D. As the particle energy of matter increases, the motion of atoms remains
unchanged
Answer:
The correct option is A
Explanation:
Generally, when the temperature of matter is low and starts to cool, the kinetic energy of it's particles decreases which causes the motion of the atoms within it's particles to also decrease. When the kinetic energy of the particles decreases, it causes the matter to form a mass by coming together since it's atoms will no longer be able to move freely as before (just like in solids) - this is the reason for the formation of ice in the freezing compartment.
From the explanation above, it can be deduced that the correct option is A
Which particles determine the atomic number of an element?
(2 Points)
Protons only
Neutrons and protons
Neutrons only
Protons and electrons
Answer:
protons and electrons
A 337 nm nitrogen laser puts out 5.00 W of power with a beam 5.90 mm in diameter. The beam is pointed directly at a pinhole which has a diameter of 1.10 mm. How many photons of light will travel through the pinhole per second? Assume that the intensity of the light is equally distributed across the whole area of the beam.
Answer:
#_foton2 = 2.96 10¹⁶ photon / s
Explanation:
We are going to solve this exercise in parts, first we will calculate how many photons are in the beam and then the amount that pass through the pinhole.
To find the energy of a photon, let's use the Planck relationship
E = h f
c = λ f
we substitute
E₀ = h c /λ
E₀ = 6.63 10⁻³⁴ 3 10⁸/337 10⁻⁹
E₀ = 5.90 10⁻¹⁹ J
Now we can use a direct ratio rule to find out the number of photons in the beam. If 1 photon has an energy E₀, how many photons are in an energy 5.00W
# _foton = 1 5/ E₀ = 1 5 / 5.90 10⁻¹⁹
#_foton = 8.5 10¹⁸ photons / s
This number of photons is uniformly distributed in the area of the circle with diameter 5.90mm = 5.90 10⁻³m
R= d/2= 2.95 10⁻³ m
r = d/2 = 0.55 10⁻³ m
let's find the beam area
A = π R²
A = π (2.95 10⁻³)²
A = 2.73 10⁻⁵ m²
the pinhole area
a = π r²
a = π (0.55 10⁻³)²
a = 9.50 10⁻⁷ m²
Let's use another direct ratio (rule of three) if there are 8.5 1018 photons / s in an area A how many photons pass through the area at
# _foton2 = 8.5 10¹⁸ a / A
# _fotn2 = 8.5 10¹⁸ 9.50 10⁻⁷ /2.73 10⁻⁵
#_foton2 = 2.96 10¹⁶ photon / s
Which of the following is not permitted, based on the second law of
thermodynamics?
A. Heat flowing from cold to hot
B. A machine that is 80% efficient
C. Heat being completely converted into mechanical energy
D. Heat flowing from hot to cold
Answer:
A. Heat flowing from cold to hot
Explanation:
The second law of thermodynamics speaks about entropy and directions of processes. These directions go only in one direction, just as time moves only in one direction, as we know it. It is impossible to see time moving forward in a different sense. In the same way, the processes associated with heat transfer, go in a single direction this direction is associated with bodies at different temperatures. Where heat is transferred from a higher temperature body to a lower temperature body.
Heat transfer processes from a cold body to a hot body, do not exist and can not be achieved in a natural way.
Answer:
C
Explanation:
A person picking apples stand on a ladder 3.0 m above the ground. He throws them into
a basket 2.0 m away. How fast must the person throw the apple in order for it to land in
the basket?
Answer:
The speed the apple must be thrown in order for it to land in the basket is 2.554 m/s.
Explanation:
Given;
height above the ground, h = 3.0 m
horizontal distance, X = 2.0 m
The time to drop from the given height;
h = ¹/₂gt²
[tex]t = \sqrt{\frac{2h}{g} }\\\\t = \sqrt{\frac{2*3}{9.8} }\\\\t = 0.783 \ s[/tex]
The horizontal speed traveled by the apple is given by;
vₓ = X / t
vₓ = 2 / 0.783
vₓ = 2.554 m/s
Therefore, the speed the apple must be thrown in order for it to land in the basket is 2.554 m/s.
How fast would a rock fall in a vacuum? Based on this, why would Aristotle say that there could be no such thing as a vacuum?
Answer:
In real measurements, the acceleration that is measured is always less than the acceleration of gravity, therefore there must be a force that opposes the movement, which is why Aristotle says that vacuum stenos
Explanation:
When a rock starts the vacuum, there are no friction forces that make its movement, therefore, if close to the Earth, the rock has an acceleration equal to the acceleration of gravity.
In real measurements, the acceleration that is measured is always less than the acceleration of gravity, therefore there must be a force that opposes the movement, which is why Aristotle says that vacuum stenos
cloudy nights are usually warm because
Answer:
When you have a cloudy night, the clouds prevent heat from escaping through the atmosphere and into space.
The clouds act like a blanket and trap the heat it, and that is why every time you have a cloudy night, it is always warmer than a clear night.
An object with a mass of 14 kg experiences a force of 12 N. What is the acceleration of the object? Help, please!! <3
Answer:
6/7 kg
Explanation:
We are given:
Mass of the object (m) = 14 kg
Force applied (F) = 12 N
Acceleration of the Object:
From newton's second law of motion, we know that:
F = ma
Replacing the variable with the given values
12 = 14 * m
m = 12 / 14 [dividing both sides by 14]
m = 6/7 kg
Hence, the Object has a mass of 6/7 kg
please answer this question
Answer:
Pic not clear.........
in the velocity and acceleration are in the same direction the speed of the object decreases
true or false
Answer:
False
Explanation:
Im pretty sure the answer is false
What are the results if you fail to turn the Bucky on?
Answer:
♡ here's your answer ♡
if you fail to turn the bucky on, it might result in your life being dangered since if in one case, your protecting yourself and you don't have it on, you could get killed ☆
- madeline/madi
✧･ﾟ: *✧･ﾟ:･ﾟ✧*:･ﾟ✧･ﾟ
Explanation:
The relative age of lower layers of rock is _______ than the
relative age of rocks above them.
Answer:
the relative age of lower layers of rock is more than the relative age of rocks above them.
what is a circit pls tell me
Answer:
A closed loop that electrons can travel in.
Explanation: