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Work and energy

A battery lights a bulb. Describe the energy changes involved in the process.

10/11/2024

Science

9th

Work and 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?

10/11/2024

Science

9th

Work and energy

Look at the activities listed below. Reason out whether or
not work is done in the light of your understanding of the
term ‘work’.
• Suma is swimming in a pond.
• A donkey is carrying a load on its back.
• A wind-mill is lifting water from a well.
• A green plant is carrying out photosynthesis.

• Food grains are getting dried in the sun.
• A sailboat is moving due to wind energy.
• An engine is pulling a train.

10/11/2024

Science

9th

Work and energy

Define average power.

10/11/2024

Science

9th

Work and energy

A lamp consumes 1000 J of
electrical energy in 10 s. What is
its power?

10/11/2024

Science

9th

Work and energy

Define 1 watt of power.

10/11/2024

Science

9th

Work and energy

What is power?

10/11/2024

Science

9th

Work and energy

The kinetic energy of an object of
mass, m moving with a velocity
of 5 m s–1 is 25 J. What will be its
kinetic energy when its velocity
is doubled? What will be its
kinetic energy when its velocity
is increased three times?

10/11/2024

Science

9th

Work and energy

Write an expression for the kinetic
energy of an object.

10/11/2024

Science

9th

Work and energy

 What is the kinetic energy of an
object?

10/11/2024

Science

9th