Potential Energy

Q.

A weight lifter of power $1960watt$ lifts a load of mass $M$ from the ground to a height of $2m$in $3seconds$. The value of $M$ is

1. $100kg$

2. $200kg$

3. $300kg$

4. $400kg$

Q.

What is potential energy ? State its unit.

Q.

A small body of mass $m$ falls to the earth from an infinite distance away. What will be its velocity on reaching the earth? (Radius of the earth is $R$, acceleration due to gravity on the surface of the earth is $g$):

Q.

A cart is loaded with a brick and pulled at constant speed along an inclined plane to the height of a seat-top. If the mass of the loaded cart is $3.0kg$ and the height of the seat top is $0.45m$, then what is the potential energy of the loaded cart at the height of the seat-top?

Q.

Two bodies of same masses are placed at a height h and 2h.

Compare their gravitational potential energy.

Q. The energy possessed by a body by virtue of its height is called .

1. kinetic energy
2. potential energy
3. heat energy

Q.

The energy possessed by a body due to its position or configuration is called ___ energy.

Q.

Two boys were playing with the same ball on a level ground. One of the boys throws the ball on the third floor of the building which is at a height of 5 m and the other boy manages to throw on the fourth floor which is at a height of 7 m from the level ground. Then the ratio of the potential energy gained by the ball in both cases is:

1. 2: 3

2. 5: 7

3. 3: 2

4. 1: 1

Q.

The gravitational potential energy stored in a box of weight 150kgf is 1.5*10000J . Find the height of the box. Take 1kgf=10N

Q.

A man weighing $70\mathrm{kg}$ carries a weight of $10\mathrm{kg}$ to the top of the tower $100\mathrm{m}$ high. Calculate the work done.

Q.

The weight of a person on a planet A is about half that on the earth. He can jump up to a height of $0.4m$ on the surface of the earth. How high can he jump on planet A?

Q.

Give an example of a body having potential energy due to a change of shape.

Q.

Name the form of energy stored in a wound up spring of a watch.

Q. Are running train processes which type of energy

Q. Define potential energy.
An object thrown at a certain angle to the ground moves in a curved path and falls back to the ground. The initial and the final points of the path of the object lie on the same horizontal line. What is the work done by the force of gravity on the object? [3 MARKS]

Q. Rahul takes 1 minute to raise a box to a height of 1 metre and Rohan takes $\frac{1}{2}$ minute to do so. Comment on the energy by the two.

1. Energy spent by the Rahul is more.
2. Energy spent by both is zero
3. Energy spent by both Rahul and Rohan is same.
4. Energy spent by the Rohan is more

Q.

What would be the gravitational potential energy of an object whose mass is 1 kg and is at a height of 10 meters?

1. 50J

2. 49J

3. 10J

4. 98J

Q.

Two bodies of equal weight are kept at heights of $h$ and $1.5h$ respectively. The ratio of their P.E. is

1. $3:2$

2. $2:3$

3. $1:1$

4. none of these

Q.

Give one example of a body that has potential energy, in each of the following :

(a) due to its position at a height,

(b) due to its elongated stretched state.

Q.

What would be the gravitational potential energy of an object whose mass is $\text{1kg}$ and is at a height of $\text{10m}$?$(takeg=9.8m{s}^{-}2)$

1. 10J

2. 50J

3. 98J

4. 49J

Q.

Two paths lead to the top of a hill. One is shorter and steeper and the second one is longer but less steep. For which of the two paths is the gain in potential energy more?

1. Path I

2. Path II

3. Same for both the paths

4. Data insufficient

Q.

Two boys were playing with a ball on a level ground. One of the boys throws the ball on the third floor of the building which is at a height of 5 m and the other boy manages to throw on the fourth floor which is at a height of 7 m from the level ground. Find the ratio of the work done by both the boys?

1. 1 : 1

2. 2 : 3

3. 5 : 7

4. 3 : 2

Q.

A boy lifts a luggage from height 2m to 4m. The potential energy will become___the initial.

1. half

2. double

3. one-third

4. one- fourth

Q.

State two factors on which the potential energy of a body at a certain height above the ground depends.

Q.

Pressure varies with area $\left(\mathrm{A}\right)$ as :

1. $\mathrm{A}$

2. $1/\mathrm{A}$

3. ${\mathrm{A}}^2$

4. $1/{\mathrm{A}}^2$

Q.

A large box is raised to a vertical height of $8m$, when the energy spent is $64,000J$. Calculate the mass of the box. [ Take $g=10m{s}^{-2}$]

Q.

Potential energy depends on:

1. position of the object

2. shape of the object

3. Mass of the object

4. All of these

Q.

To what height should an object of mass $\text{2kg}$ be raised so that its potential energy is $\text{980J}$?$g=9.8m{s}^{-}2$

1. 50 cm

2. 100 m

3. 50 m

4. 100 cm

Q.

In a hydro-electric power plant:

1. Potential energy possessed by stored water is converted into electricity

2. Kinetic energy possessed by stored water is converted into potential energy

3. Electricity is extracted from water

4. Water is converted into steam to produce electricity

Q. what is gravitational potential energy