Kinetic Energy

Q.

A light and heavy body have equal momentum. Which one has greater kinetic energy?

1. Light body

2. Heavy body

3. Both body have same kinetic energy

4. None of the above

Q.

In a direct impact, loss in kinetic energy is given by
$\Delta K=\frac{M_1{M}_2}{2(M_1+M_2)}.(V_1-V_2{)}^2(1-k^2)$
with usual notations (except k). The quantity k will have dimensional formula:

1. $\left[M^0{L}^0{T}^0\right]$

2. $\left[M^0{L}^2{T}^{-2}\right]$

3. $\left[ML{T}^{-1}\right]$

4. $\left[M^0{L}^1{T}^{-1}\right]$

Q.

Two bodies of masses m₁ and m₂ having equal kinetic energies. If p₁ and p₂ are their momentum respectively, Then the ratio of p₁ and p₂ is.

1. m₁/m₂

2. m₂/m₁

3. 

4. m₁²/m₂²

Q.

What is the work to be done to increase the velocity of a car from 30 km per hour to 60 km per hour if the mass of the car is 1500 kg?

Q.

Write an expression for the kinetic energy of a body of mass m moving with a velocity v.

Q.

Define kinetic energy, give two examples of kinetic energy.

Q.

Derive the formula for the kinetic energy of an object of mass m, moving with velocity v .

Q. Examples of law of conservation of energy...

Q.

If the velocity of a moving car is halved, its kinetic energy would

1. Remain same

2. Become Half

3. Become one fourth

4. Double

Q. Can a body have energy without having momentum? Why?

Q.

Which would have a greater effect on the kinetic energy of an object : doubling the mass or doubling velocity ?

Q. Question 3
The kinetic energy of an object of mass, m moving with a velocity of $5m{s}^{-1}$ is 25 J. What will be its kinetic energy when its velocity is doubled? What will be its kinetic energy when its velocity is increased three times?

Q.

A ball is thrown vertically upwards. Its velocity keeps on decreasing. What happens to its kinetic energy when its reaches the maximum height?

1. Kinetic energy is maximum at maximum height

2. Kinetic energy is half of initial value

3. Kinetic energy is zero

4. Kinetic energy is double

Q.

A body covers one half of its journey at $40{\mathrm{ms}}^{-1}$and the next half at $50{\mathrm{ms}}^{-1}$. its average velocity is

1. $44.4{\mathrm{ms}}^{-1}$

2. $50{\mathrm{ms}}^{-1}$

3. $45{\mathrm{ms}}^{-1}$

4. $40{\mathrm{ms}}^{-1}$

Q. Factors affecting the kinetic energy

Q.

Draw a diagram to show the energy changes in an oscillating simple pendulum. Indicate in your diagram how the total mechanical energy in it remains constant during the oscillation.

Q.

A rocket is moving up with velocity v. If the velocity of the rocket is tripled, what will be the ratio of kinetic energies? [2 MARKS]

Q.

How does the kinetic energy of a moving body depend on its (i) speed, and (ii) mass?

Q.

How fast should a man of 50 kg run so that his kinetic energy be 625 j ?

Q.

The kinetic energy of an object depends on its mass and velocity.

1. True
2. False

Q. A body of mass $m$ has a momentum $p$. What is its kinetic energy?

1. $\frac{p^2}{2m}$
2. $\frac{p^2}{m}$
3. $\frac{p^2}{2}$
4. $\frac{p}{m^2}$

Q.

if a body of mass 3 kg is dropped from top of a tower of height 50 m., then K.E.bafter 3 sec will be (ans=735J)

Q.

What are the two forms of mechanical energy?

Q.

A light and a heavy object have the same momentum. Which one of the following statements is correct regarding the kinetic energy of these two objects?

1. $(K.E{)}_l>(K.E{)}_h$

2. $(K.E{)}_l=(K.E{)}_h$

3. $(K.E{)}_h=1.5\times (K.E{)}_l$

4. $(K.E{)}_h=2\times (K.E{)}_l$

Q.

A body of 2 kg falls from rest. What will be its kinetic energy during the fall at the end of 2 s ? (Assume g = 10 $m/s^2$)

Q.

A car is moving with a uniform velocity of 54 kilometres per hour (km/h). What is the kinetic energy of a boy of mass 40 kg sitting in the car?

Q.

Name two forms of mechanical energy.

Q.

How is the kinetic energy of a moving cart affected if its velocity is reduced to $\frac{1}{3}$rd of the initial velocity?

1. Kinetic energy reduces to $\frac{1}{3}$rd its initial value

2. Kinetic energy increases to $\frac{1}{3}$rd its initial value

3. Kinetic energy reduces to $\frac{1}{9}$th its initial value

4. Kinetic energy increases to $\frac{1}{9}$th its initial value

Q.

Find the momentum of a body of mass 100 g having a kinetic energy of 20 J.

Q.

Two bodies of equal masses move with uniform velocities $v$ and $3v$ respectively. Find the ratio of their kinetic energies.