NCERT Class-9 Science Solutions: Chapter 11-Work And Energy Part 1

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Multiple Choice Questions

Question 1:

When a body falls freely towards the earth, then its total energy

  1. Increases

  2. Decreases

  3. Remains constant

  4. First increases and then decreases

Answer: C

Image the moon toward the earth

Image the Moon Toward the Earth

Question 2:

A car is accelerated on a levelled road and attains a velocity of its initial velocity. In this process the potential energy of the car

  1. Does not change

  2. Becomes twice to that of initial

  3. Becomes 4 times that of initial

  4. Becomes 16 times that of initial

Answer: A

Question 3:

In case of negative work the angle between the force and displacement is

Answer: D

Image the force and displacement

Image the Force and Displacement

Question 4:

An iron sphere of mass has the same diameter as an aluminum sphere of mass is . Both spheres are dropped simultaneously from a tower. When they are above the ground, they have the same

  1. Acceleration

  2. Momenta

  3. Potential energy

  4. Kinetic energy

Answer: A

Gravity equation free fall acceleration of body

Gravity Equation Free Fall Acceleration of Body

Question 5:

A girl is carrying a school bag of mass on her back and moves on a levelled road. The work done against the gravitational force will be

Answer: D

Work done against the gravitational force

Work Done Against the Gravitational Force

Question 6:

Which one of the following is not the unit of energy?

  1. Joule

  2. Kilowatt-hour

  3. Newton meter

  4. kilowatt

Answer: C

Question 7:

The work done on an object does not depend upon the

  1. Displacement

  2. Force applied

  3. Angle between force and displacement

  4. Initial velocity of the object

Answer: D

Image the initial velocity of the object

Image the Initial Velocity of the Object

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