Conversion of P.E to K.E

Q.

Give an example to show the conversion of potential energy to kinetic energy when put in use.

Q.

an elastic band can store energy

<a> explain how the elastic band can be made to store energy

(b) how can its energy be released

Q. Find the potential energy possessed by an object of mass 6 kg when it is at height of 5 m above the ground. Take acceleration due to gravity $g=10m{s}^{-2}.$

1. 100 J
2. 500 J
3. 1000 J
4. 300 J

Q.

Which of the following is not an example of potential energy?

1. A stretched rubber band

2. A moving car

3. Water stored in the reservoir of dam

4. A compressed spring

Q. An object of mass $2kg$ has the potential energy of $980J$. The height of the object is. Take $g=9.8m{s}^{-}2$

1. $25m$
2. $50m$
3. $20m$
4. $27m$

Q.

A stone of mass $500g$ is raised from a height of $2m$ to $4m$. find the change in its potential energy.

Q.

An object is falling from a terrace of height $20m$. At what point does it have maximum kinetic energy?

1. 10m height

2. 20m height

3. When object touched the ground floor

4. Just before touching the ground floor

Q.

If a stone of mass m falls a vertical distance d, the decrease in gravitational potential energy

1. mg/d

2. md²/2

3. mgd

4. md/g

Q.

A ball of mass $1kg$ moving with a velocity of $10m/s$ at time $t=1s$. At time $t=2s$, it is moving with velocity of $20m/s$. Net force that acted on the body in this duration of time is

1. $100N$

2. $10N$

3. $20N$

4. $110N$

Q. Find the potenial energy possessed by a body of mass $4kg$ when it is at height of $10m$ above the ground. (Take $g=10m{s}^{-2}$ )

1. 400

Q.

What happens to the potential energy of an object, if its mass is doubled and its lifted height is halved from its initial state?

1. Becomes quadruple

2. Becomes double

3. Becomes half

4. Remains same

Q. Two bodies of same mass are placed at height h and 2h above ground. Compare their gravitational potential energy. [2 marks]

Q.

We know that If a ball of mass 1 kg is kept at a height 10 m possess potential energy “mgh” i.e. $(1\times 10\times 10)=100$ J. (Taking earth surface as reference, where m = mass of object, g = acceleration due to gravity, h = height of object from earth surface.) what will be the kinetic energy of the ball when the ball is allowed to fall freely from a height 10m from the surface of earth and it hits the ground? (take g = 10 $m/s^2$ and neglect air drag)

1. 100 J

2. 50 J

3. 10 J

4. 0 J

Q.

What action is being applied by the character while throwing the ball?

Q. What is the type of energy that can be possessed by an object at rest?

1. Thermal E.
2. Kinetic E.
3. Sound E.
4. Potential E.

Q. Which of the following statements is true?

1. Gravity is a non-conservative force.
2. Work done by friction is path dependent.
3. Work done by gravity is path dependent.
4. Friction is a conservative force.

Q.

An object of weight 40 N is released from a height of 10 m. Its kinetic energy just before it hits the ground is:

1. 2800 J
2. 1200 J
3. 3920 J
4. 400 J

Q.

The potential energy is least when you are ___.

1. sitting on a chair

2. sleeping on the ground

3. standing on the ground

4. sitting on the ground

Q. A ball rolling on a grass field comes to rest due to:

1. Friction
2. Density
3. Acceleration
4. Gravity

Q. When two different stones of masses $8kg$ and $16kg$ are taken to the same height, then ratio of their potential energies respectively is.

1. $1:3$
2. $1:1.5$
3. $1:1$
4. $1:2$

Q.

What is the work done to lift a body of mass 5 kg to a height of 50 m from the ground (in J)? (g=10 $m{s}^{-2}$)

1. $250$

2. $2.5\times {10}^{10}$

3. $2.5\times {10}^3$

4. $2.5\times {10}^{-4}$

Q. Differentiate between potential energy and kinetic energy.

Q. Question 9
A body is falling from a height h, after it has fallen a height $\frac{h}{2}$, it will possess

(a) only potential energy
(b) only kinetic energy
(c) half potential and half kinetic energy
(d) more kinetic and less potential energy

Q.

What would be the gravitational potential energy of an object whose mass is $\text{1 kg}$ and is at a height of $\text{10 m}$?

1. 50 J

2. 49 J

3. 10 J

4. 98 J

Q. The P.E.of a body at a certain height is 200J when it is released. The K.E when it just touches the surface is:

1. Equal to potential energy
2. Lesser than potential energy
3. Greater than potential energy
4. None of the above

Q.

Two paths lead to the top of a hill. The first path is short and steep. The second path is longer and steeper. The gain in potential energy is more for which path?

1. Path I

2. Path II

3. Same for both the paths

4. Data insufficient

Q.

Potential energy is independent of:

1. Position of the object.
2. Shape of the object.
3. Mass of the object.
4. Path taken by the object.

Q.

Water stored in a dam possesses ___.

1. potential energy

2. no energy

3. electrical energy

4. kinetic energy

Q. Potential energy depends on:

1. Mass of the object
2. Velocity of the object
3. Shape of the object
4. Position of the object

Q.

Potential energy possessed by an object of mass m and raised to a height 2h above the earth's surface is:

1. mgh/2

2. zero

3. mgh

4. 2mgh