EASY

Earn 100

Unit of work is

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Important Questions on Work and Energy

MEDIUM

Science>Physics>Work and Energy>Work

Consider a drop of rain water having mass

1 g

falling from a height of

1 km

. It hits the ground with a speed of

50 m s^{- 1}

. Take

g

constant with a value

10 m s^{- 2}

. The work done by the (i) gravitational force and the (ii) resistive force of air is

EASY

Science>Physics>Work and Energy>Work

Heat and work done by the heat was discovered by

EASY

Science>Physics>Work and Energy>Work

Assertion $(A)$ : The work done by the electrostatic force is zero when a point charge moves in a circular path around another charge.

Reason $(R)$ : The dot product of force and displacement vectors gives work done.

EASY

Science>Physics>Work and Energy>Work

The work done to raise a mass

m

from the surface of the earth to a height

h

, which is equal to the radius of the earth is:

HARD

Science>Physics>Work and Energy>Work

A force is applied upon a body of 40 kg then its velocity increases from 1
metre/second to 2 metre/second. Determine work done by the force.

EASY

Science>Physics>Work and Energy>Work

A particle of mass

10 g

is thrown vertically upwards with a speed of

20 m s^{- 1}

. The work done by the gravitational force during the time the particle moves upward is

EASY

Science>Physics>Work and Energy>Work

Spring constant of a spring is

K = 6 \times 10^{3} N / m

. Work done to stretch it

10^{- 2} m

from mean position is

EASY

Science>Physics>Work and Energy>Work

A force of

40 N

acts on a body, and body moves through a distance of

2

metre at an angle of

45 °

in the direction of the force. The work done by the force is

HARD

Science>Physics>Work and Energy>Work

An object of 40 kg mass is moving with 5 m/s velocity. Now force is applied on the object such that its velocity increases to 10 m/s. Calculate the work done by the force.

MEDIUM

Science>Physics>Work and Energy>Work

A body is displaced by 10 m when maximum work of 200 joules is done on it. Calculate the force acting on this body.

MEDIUM

Science>Physics>Work and Energy>Work

Derive a relationship between SI and CGS units of work.

EASY

Science>Physics>Work and Energy>Work

Convert 1 kilowatt-hour into joules.

HARD

Science>Physics>Work and Energy>Work

A pump on the ground floor of a building can pump up water to fill the tank of

30 m^{3}

15

min. If the tank is

40 m

above the ground, and the efficiency of the pump is

30 %,

the power consumed by the pump is

(g = 10 m / s^{2})

EASY

Science>Physics>Work and Energy>Work

A person of mass

50 kg

climbs a tower of height

72 m

. Calculate the work done. (take

g = 10 \frac{m}{s^{2}}

EASY

Science>Physics>Work and Energy>Work

When a body is thrown up, work done by the gravity of the earth on the body is

EASY

Science>Physics>Work and Energy>Work

A magnetic crane lifts a mass of

1000 kg

through a height of

50 m

. Calculate the work done by the crane. (Take

g = 10 \frac{m}{s^{2}}

)

EASY

Science>Physics>Work and Energy>Work

When is the work done by a force on a body said to be positive? Give two examples.

EASY

Science>Physics>Work and Energy>Work

What is the work done in holding a

15 kg

suitcase while waiting for a bus for

15 minutes

EASY

Science>Physics>Work and Energy>Work

When the force applied on a body is increased, the work done on it

EASY

Science>Physics>Work and Energy>Work

From the following activity listed below, state whether or not work is done. Give your reason as well.

A ball is thrown upwards in the air.

Unit of work is

Important Questions on Work and Energy

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