Work and Energy

Q. Capacity to do work is called_______.

1. force
2. displacement
3. distance
4. energy

Q.

Distinguish between labour hour rate and machine hour rate method

Q.

What is the amount of work done by a weight lifter in holding a weight of $100kg$ on his shoulders for $40$ seconds?

Q.

Which of the following is not a simple machine?

1. knife

2. crowbar

3. a pair of scissor

4. paper

Q. What is the work done if a force of 5 N moves a body through a distance of 5 m?

1. 0 J
2. 25 J
3. 20 J
4. 1 J

Q.

Which of the following is/are machines?

1. Hammer

2. Spade

3. Scissors

4. Spanner

Q.

Choose the correct one from the following.

1. A simple machine is a device that increases human efforts.

2. A simple machine is a device that always maintains the magnitude of a force.

3. A simple machine is a device that changes the direction or magnitude of a force.

4. A simple machine is a device that changes the magnitude of a force.

Q.

Give an example of force acting perpendicular to the direction of displacement.

Q.

What is the difference between simple machine and complex machine ?

Q. Which among the following quantities have joule as their S.I unit?

1. Work done
2. Energy
3. Force
4. Distance

Q.

A force of 25 N acts on a body and produces a displacement of 5 m. Calculate the work done?

Q.

Give some examples where a pulley is used as a simple machine.

Q.

The resistive or opposing force to be overcome by a machine is called ___

Q.

Look at the activity listed here. Reason out whether or not work is done in the light of your understanding of the term work. Food grains are getting dried in the sun.

Q. A boy is standing with a heavy bag. Which of the following is/are true?

1. He is spending some energy on the bag.
2. He is applying a force on the bag.
3. Kinetic energy is converted into potential energy.
4. Work done by the boy is zero.

Q.

A force of $100N$ acts on a body and displaces it through a distance of $15m$. Find the work done by the force in SI units.

Q. Calculate the work done when Ram applies a force of $50N$ on a wooden block and moves it by $15m$ in the same direction.

Q.

A force of $8kgf$ raises a load of $4kg$ through $5m$ first and then the same force raises another load of $6kg$ through the same distance. So,

1. It does greater work in raising the $6kg$ load

2. It does less work in raising the $6kg$ load

3. It does the same work in raising both the loads

4. It cannot be said unless the time in which the work is done is given.

Q.

Give the two conditions that are necessary for work to be done.

Q. Ram carried four balls of metal through a height of 10 metres. The process involved some work done. If he carries two similar balls of metal through a height of 20 metres, work done in this case is ______ the first case. (Assume the balls are of weight $1N$ each.)

1. more than
2. less than
3. equal to
4. double

Q.

Consider the following statements:

A. A person standing for a long time with a suitcase on his head does no work in terms of physics
B. There cannot be any displacement of an object in the absence of any force acting on it.
C. The law of conservation of energy is valid in all situations and for all kinds of transformations

Which of these statement(s) is/are correct?

1. A and B

2. A and C

3. B and C

4. All are correct

Q.

What is a simple machine?

Q. If the force applied on an object is 4 N and the displacement is 5 m, then the work done is .

1. 20 J
2. 30 J
3. 50 J
4. 40 J

Q.

A horse does a work of $6250J$ while applying a force of $250N$ in pulling a tonga. The displacement produce in tonga is:

1. $12.5m$

2. $15m$

3. $25m$

4. $20m$

Q. Ram carried a bag of $10kg$ to a point which is $10m$ away on a horizontal ground. Then he carried the same bag to the initial position. What is the amount of work done by Ram in this case?

1. $0Joule$
2. $5Joule$
3. $10Joule$
4. $20Joule$

Q.

give one word.

1)a machine which lets our job done with less effort.

2)a simple machine which changes the direction of force and makes work easy.

30 the arrangement to lift heavy loads.

Q.

Koushal picks up a box from the ground and places it back. The work done here is ___.

1. 0 Joules

2. 30 Joules

3. 50 Joules

4. 40 Joules

Q.

Choose the correct one from the following.

1. A simple machine is a device that changes the direction or magnitude of a force.

2. A simple machine is a device that changes the magnitude of a force.

3. A simple machine is a device that increases human efforts.

4. A simple machine is a device that always maintains the magnitude of a force.

Q. The work is said to be done, if a force acting on a body displaces the body.

1. False
2. True

Q.

Use of ........................ does not decrease the force required but it changes the direction of force ?

1. Wedge

2. Screw

3. Wheel and Axle

4. Pulley