EASY

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Total energy of an isolated system-

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Important Questions on Work, Energy and Power

MEDIUM

Physics>Mechanics>Work, Energy and Power>Law of Conservation of Energy

The total energy of an object falling freely towards the ground _____.

(Choose from: decreases, remains unchanged, increases, increases in the beginning and then decreases)

EASY

Physics>Mechanics>Work, Energy and Power>Law of Conservation of Energy

A U-tube of cross section

A

and

2 A

as shown contains liquid of density

d

. Initially, the liquid in the two arms are held with a level difference

h

. After being released the levels equalize after some time. The work done by gravity forces on the liquid in the process is -

Question Image

EASY

Physics>Mechanics>Work, Energy and Power>Law of Conservation of Energy

A particle is released from a height h. At a certain height, its kinetic energy is two times its potential energy. Height and speed of the particle at that instant are

EASY

Physics>Mechanics>Work, Energy and Power>Law of Conservation of Energy

A ball of mass

2 kg

and another of mass

4 kg

are dropped together from a

60

feet tall building. After a fall of

30

feet each towards earth, their respective kinetic energies will be in the ratio of

MEDIUM

Physics>Mechanics>Work, Energy and Power>Law of Conservation of Energy

U -

shaped smooth wire has a semi-circular bend of radius

R

between

A

and

B

. It is held fixed in a vertical plane. A bead of mass

m

is released from height

h

(above

A

) and slides smoothly along the wire to reach the same height on other side of the wire. It is given that

h ≫ R

Consider the motion of the bead between

A

and the lowest point

C

of the wire. The ratio of change in magnitude of velocity of the particle at

A

to the magnitude of change in its velocity at

C

is nearly equal to

EASY

Physics>Mechanics>Work, Energy and Power>Law of Conservation of Energy

An object is dropped from a certain distance when she is at half distance she is ______ in it?

EASY

Physics>Mechanics>Work, Energy and Power>Law of Conservation of Energy

A ball is thrown vertically up with a velocity

20 \frac{m}{s}

. At what height will its kinetic energy be half its original value?

HARD

Physics>Mechanics>Work, Energy and Power>Law of Conservation of Energy

Prove that the kinetic energy of a freely falling object on reaching the ground is nothing but the transformation of its initial potential energy.

HARD

Physics>Mechanics>Work, Energy and Power>Law of Conservation of Energy

Two inclined frictionless tracks, one gradual and the other steep meet at A, from where two stones are allowed to slide down from rest, one on each track (Figure). Will the stones reach the bottom at the same time? Will they reach there with the same speed? Explain. Given