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Which of the following is non-conservative force?

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Important Questions on Work, Energy and Power

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Science>Physics>Work, Energy and Power>Conservative and Non-conservative Forces

When a ball of mass

50 g

is thrown upwards, it raises to a maximum height of

100 m .

At what height its

K . E

. will be reduced to

70 % ?

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Science>Physics>Work, Energy and Power>Conservative and Non-conservative Forces

Two bodies having kinetic energy in the ratio

4 : 1

, are moving with same linear velocity. The ratio of their masses is

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Science>Physics>Work, Energy and Power>Conservative and Non-conservative Forces

The potential energy of a particle in a central field has the form

U (r) = \frac{1}{r^{2}} - \frac{1}{r},

where

' r'

is the distance from the centre of the field. The magnitude of the maximum attractive force in Newton is

EASY

Science>Physics>Work, Energy and Power>Conservative and Non-conservative Forces

If the momentum of the body increases by

10 %

then the increase in Kinetic energy of the body is

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Science>Physics>Work, Energy and Power>Conservative and Non-conservative Forces

Two equal masses are attached to two each of a spring of spring constant

k

. The masses are pulled out symmetrically to stretch the spring by a length

x

over is natural length. The work done by the spring on each mass is

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Science>Physics>Work, Energy and Power>Conservative and Non-conservative Forces

A particle moves in a straight line with retardation proportional to its displacement. Its loss of kinetic energy for any displacement

x

is proportional to

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Science>Physics>Work, Energy and Power>Conservative and Non-conservative Forces

A car driver is trying to jump across a path as shown in figure by driving horizontally off a cliff $' X'$ at the speed $10 m s^{- 1}$ . When he touches peak $Z$ (ignore air resistance), what would be speed? (use $g = 10 m s^{- 2}$ )

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MEDIUM

Science>Physics>Work, Energy and Power>Conservative and Non-conservative Forces

If the potential energy between two molecules is given by

U = \frac{A}{r^{6}} - \frac{B}{r^{12}},

then at equilibrium, separation between molecules, and the potential energy are:

EASY

Science>Physics>Work, Energy and Power>Conservative and Non-conservative Forces

If the kinetic energy of a moving body becomes four times its initial kinetic energy, then the percentage change in its momentum will be:

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Science>Physics>Work, Energy and Power>Conservative and Non-conservative Forces

A car of mass

1000 kg

collides with a horizontally mounted spring and comes to rest. If the speed of the car just before the collision was

10 m s^{- 1}

and spring constant

k = 10^{4} N m^{- 1}

then what is the maximum compression of the spring,

EASY

Science>Physics>Work, Energy and Power>Conservative and Non-conservative Forces

Two balls A and B are released towards point W from point X and point Z respectively, on a perfectly smooth track as shown in the figure. The balls move along the track without losing contact. What will be the ratio of their speeds (

\frac{v_{A}}{v_{B}}

) at point W?
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EASY

Science>Physics>Work, Energy and Power>Conservative and Non-conservative Forces

A bullet of mass $10 g$ pierces through a plate $A$ of mass $500 g$ and then gets embedded into a second plate $B$ of mass $1.49 kg$ as shown in the figure. Initially the two plates $A$ and $B$ are at rest and move with same velocity after collision. The percentage loss in the initial kinetic energy of the bullet when it is between the plates $A$ and $B$ is_______. (Neglect any loss of material of the plates during the collision)