Potential Energy of an Object at a Height

Q.

How much water a pump of $2kW$ can raise in one minute to a height of $10m$. Take $g=10m/s^2$?

Q.

A body of mass 100 kg is lifted up by 10 m. Find :

(i) the amount of work done.

(ii) potential energy of the body at that height (value of g = 10 $m/s^2$)

Q. How the value of 'g' varies with altitude?

Q.

Define 1 joule. [1 MARK]

Q.

What kind of energy transformation takes place when a toy is dropped from certain height?

Q.

If one chamber has a ${\psi }_w$of - 2000 KPa, and the other - 1000 K Pa, which chamber has the higher $\psi$?

Q.

A body of mass 2 kg is thrown vertically upwards with an initial velocity of 20 m/s. What will be its potential energy at the end of 2 s ? (Assume g = $10m/s^2$).

Q. a man lifts a luggage of 20 kg and puts it on his head 1.7 m above the ground.what is the work done by the man on the luggage if g=10 m/s^2

Q.

How much work is done when a body of mass m is raised to a height h above the ground ?

Q.

A$2kg$ ball is dropped from a height of $10m$. Find its kinetic energy just before hitting the ground. [Take g $=10m{s}^{-2}$.]

Q. A flying bird has potential energy as well as knetic energy. Explain

Q.

A girl weighing 400 N climbs a vertical ladder. If the value of g be 10 $m{s}^{-2},$ the work done by her after climbing 2 m will be:

(a) 200 J

(b) 800 J

(c) 8000 J

(d) 2000 J

Q.

A boy weighing $50kg$ climbs up a vertical height of $100m$. Calculate the amount of work done by him. How much potential energy does he gain$(g=9.8m/s^2)$?

Q.

When the height is doubled, what happens to the potential energy of a body.

Q.

Why does an object increase its energy when raised through a height?

Q.

Two bodies A and B of equal masses are kept at heights of h and 2h respectively. What will be the ratio of their potential energies?

Q. A man weighing 50 kg lifts a weight of 30 kg to the top of building 10 m high. Find the work done by him. Take $g=9.8m/s^2$

Q.

A rock of mass $m$ is dropped to the ground from a height $h$. A second rock with a mass of $2m$ is dropped from the same height. When the second rock strikes the ground, what is its kinetic energy?

1. twice that of the first rock

2. four times that of first rock

3. the same as that of the first rock

4. half that of the first rock

Q.

If you apply 1 J of energy to lift a book of 0.5 kg, how high will it rise?

Q.

An object of mass m is allowed to fall freely from point A as shown in the figure. Calculate the total mechanical energy of the object at :
(i) Point A.
.

Q.

To what height should a box of mass 150 kg be lifted, so that its potential energy may become 7350 joules ? (g = 9.8 $m/s^2$).

Q.

If the mass of a body is doubled, its potential energy _______?

1. becomes 2 times

2. becomes 4 times

3. becomes 8 times

4. remains the same

Q.

The value of gravitational potential energy at the reference level would be.

1. Zero

2. Infinite

3. Positive

4. Negative

Q.

A crane lifts a block of mass 1000 Kg through a vertical height of 15 m in 25 sec. Calculate the power of crane. Given g = 10 m/s².

1. 600 W

2. 60 W

3. 6 W

4. 6000 W

Q.

A man X goes to the top of a building by a vertical spiral staircase. Another man Y of the same mass goes to the top of the same building by a slanting ladder. Which of the two does more work against gravity and why ?

Q.

Sarita lives on the 3rd floor of the building at a height of 15 m she carries a School Bag weighing 5.2 kg from the ground floor to her house. Find the amount of work done by her. Identify the force against which she has done the work. Take $g=10m/s^2$.

Q.

(a) On what factors does the gravitational potential energy of a body depend ?

(b) Give one example each of a body possessing : (i) kinetic energy, and (ii) potential energy.

Q.

A simple pendulum of length $1m$ has a bob of mas$10g$. Find the work done in moving the pendulum from a vertical position to a horizontal position. Take $g=10m{s}^{-2}$.

Q. Question 5
A mass of 10 kg is at a point A on a table. It is moved to a point B. If the line joining A and B is horizontal, what is the work done on the object by the gravitational force? Explain your answer.

Q.

A pendulum, swinging back and forth, rises at the end of its swing to a position $15cm$. higher than its lowest point. How fast is it going at the lowest point?