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A uniform cable of mass $M$ and length $L$ is placed on a horizontal surface such that its ${(\frac{1}{n})}^{th}$ part is hanging below the edge of the surface. To lift the hanging part of the cable upto the surface, the work done should be,

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Important Questions on Work, Energy and Power

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JEE Main

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Complete Study Pack for Engineering Entrances Objective Physics Vol 1>Chapter 6 - Work, Energy and Power>Excercise 1>Q 4

A person of mass

M

is sitting on a swing to length

L

and swinging with an angular amplitude

θ_{0}

. If the person stands up when the swing passes through its lowest point, the work done by him, assuming that his centre of mass moves by a distance

l (l < < L)

is close to,

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Complete Study Pack for Engineering Entrances Objective Physics Vol 1>Chapter 6 - Work, Energy and Power>Excercise 1>Q 5

A motor engine pumps

1800 L

of water per minute from a well of depth

30 m

and allows to pass through a pipe of cross-sectional area

30 {cm}^{2}

. Then the power of the engine is (acceleration due to gravity,

g = 10 m s^{- 2}

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Complete Study Pack for Engineering Entrances Objective Physics Vol 1>Chapter 6 - Work, Energy and Power>Excercise 1>Q 6

A ball of mass

2 kg

is thrown from a tall building with velocity,

v = (20) \hat{i} + (24) \hat{j} m s^{- 1}

at time

t = 0 s

. Change in the potential energy of the ball after,

t = 8 s

is (the ball is assumed to be in air during its motion between

0 s

and

8 s, \hat{i}

is along the horizontal and

\hat{j}

is along the vertical direction. (Take

g = 10 m s^{- 2}

)

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Complete Study Pack for Engineering Entrances Objective Physics Vol 1>Chapter 6 - Work, Energy and Power>Excercise 1>Q 7

A mass of

2 kg

initially at a height of

1.2 m

above an uncompressed spring with spring constant

2 \times 10^{4} N m^{- 1}

is released from rest to fall on the spring. Taking the acceleration due to gravity as

10 m s^{- 2}

and neglecting the air resistance, the compression of the spring in

mm

is,

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Complete Study Pack for Engineering Entrances Objective Physics Vol 1>Chapter 6 - Work, Energy and Power>Excercise 1>Q 8

A box of mass

3 kg

moves on a horizontal frictionless table and collides with another box of mass

3 kg

initially at rest on the edge of the table at height

1 m

.
The speed of the moving box just before the collision is

4 m s^{- 1}

. The two boxes stick together and fall from the table. The kinetic energy just before the boxes strike the floor is (Assume that acceleration due to gravity,

g = 10 m s^{- 2}

)

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JEE Main

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Complete Study Pack for Engineering Entrances Objective Physics Vol 1>Chapter 6 - Work, Energy and Power>Excercise 1>Q 9

A body starts from rest, under the action of an engine working at a constant power and moves along a straight line. The displacement

s

is given as a function of time

(t)

as,

A uniform cable of mass M and length L is placed on a horizontal surface such that its 1nth part is hanging below the edge of the surface. To lift the hanging part of the cable upto the surface, the work done should be,

Important Questions on Work, Energy and Power

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A uniform cable of mass $M$ and length $L$ is placed on a horizontal surface such that its ${(\frac{1}{n})}^{th}$ part is hanging below the edge of the surface. To lift the hanging part of the cable upto the surface, the work done should be,