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The dimensions of kinetic energy is-

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Important Questions on Work, Energy and Power

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Physics>Mechanics>Work, Energy and Power>Work

A small particle moves to position

5 \hat{i} - 2 \hat{j} + \hat{k}

from its initial position

2 \hat{i} + 3 \hat{j} - 4 \hat{k}

under the action of force

5 \hat{i} + 2 \hat{j} + 7 \hat{k} N

. The value of work done will be ______

J

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Physics>Mechanics>Work, Energy and Power>Work

Two persons

A

and

B

perform same amount of work in moving a body through a certain distance

d

with application of forces acting at angles

45 °

and

60 °

with the direction of displacement respectively. The ratio of force applied by person

A

to the force applied by person

B

\frac{1}{\sqrt{x}} .

The value of

x

is _________.

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Physics>Mechanics>Work, Energy and Power>Work

A wire fixed at the upper end stretches by length

∆ l

by applying a force

F

. The work done in stretching is

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Physics>Mechanics>Work, Energy and Power>Work

The work done on a particle of mass

m

by a force

K [\frac{x}{{(x^{2} + y^{2})}^{3 / 2}} \hat{i} + \frac{y}{{(x^{2} + y^{2})}^{3 / 2}} \hat{j}]

(

K

being a constant of appropriate dimensions, when the particle is taken from the point

(a, 0)

to the point

(0, a)

along a circular path of radius

a

about the origin in the x-y plane is

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Physics>Mechanics>Work, Energy and Power>Work

A person pushes a box on a rough horizontal platform surface. He applies a force of

200 N

over a distance of

15 m

. Thereafter, he gets progressively tired and his applied force reduces linearly with distance to

100 N

. The total distance through which the box has been moved is

30 m

. What is the work done by the person during the total movement of the box?

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Physics>Mechanics>Work, Energy and Power>Work

Consider a force

\vec{F} = - x \hat{i} + y \hat{j}

. The work done by this force in moving a particle from point

A (1,0)

B (0,1)

along the line segment is : (all quantities are in SI units)

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Physics>Mechanics>Work, Energy and Power>Work

A body of mass

8 kg

, under the action of a force, is displaced according to the equation

s = \frac{t^{2}}{4} m,

where

' t'

is the time. Find the work done by the force in the first

4

seconds.

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Physics>Mechanics>Work, Energy and Power>Work

The diagram shows a barrel of weight $1.0 \times 10^{3} N$ on a frictionless slope inclined at $30 °$ to the horizontal.

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The force is parallel to the slope. Whet is the work done in moving the barrel a distance of $5.0 m$ up the slope?

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Physics>Mechanics>Work, Energy and Power>Work

Two springs of spring constants

K

and

2 K

are stretched by same force. If

W_{1}

and

W_{2}

are the energies stored in them respectively then

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Physics>Mechanics>Work, Energy and Power>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.

HARD

Physics>Mechanics>Work, Energy and Power>Work

A force

(F) = - 5 \hat{i} - 7 \hat{j} + 3 \hat{k}

acting on a particle causes a displacement

(s) = 3 \hat{i} + 2 \hat{j} + a \hat{k}

in its own direction. If the work done is

14 J

, then the value of

a

is:

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Physics>Mechanics>Work, Energy and Power>Work

If a force

\vec{F} = \hat{i} - 2 \hat{j} - 4 \hat{k}

acting on a particle displaces it from

(1, 1, 1)

(2, - 1, 0),

then the work done by the force (in units of work) is

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Physics>Mechanics>Work, Energy and Power>Work

A particle moves from a point

(- 2 \hat{i} + 5 \hat{j})

(4 \hat{j} + 3 \hat{k})

when a force of

(4 \hat{i} + 3 \hat{j}) N

is applied. How much work has been done by the force?

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Physics>Mechanics>Work, Energy and Power>Work

A body moves from a position

r_{1} = (2 \hat{i} - 3 \hat{j} - 4 \hat{k}) m

to a position

r_{2} = (3 \hat{i} - 4 \hat{j} + 5 \hat{k}) m

under the influence of a constant force

F = (4 \hat{i} + \hat{j} + 6 \hat{k}) N

. The work done by the force is

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Two forces each of magnitude

10 N

act simultaneously on a body with their directions inclined to each other at an angle of

120^{o}

and displaces the body over

10 m

along the bisector of the angle between the two forces. Then the work done by each force is

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Physics>Mechanics>Work, Energy and Power>Work

A body of mass

2 kg

is projected with an initial velocity of

5 m s^{- 1}

along a rough horizontal table. The work done on the body by the frictional forces before it is brought to rest is

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Physics>Mechanics>Work, Energy and Power>Work

A body of mass

10 kg

is moving on a horizontal surface by applying a force of

10 N

in forward direction. If body moves with constant velocity. Find the work done by applied force for a displacement of

2 m

HARD

Physics>Mechanics>Work, Energy and Power>Work

A bicycle chain of length

1.6 m

and of mass

1 kg

is lying on a horizontal floor. If

g = 10 m s^{- 2}

, the work done in lifting it with one end touching the floor and the other end

1.6 m

above the floor is

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Physics>Mechanics>Work, Energy and Power>Work

5.0 kg

box rests on a horizontal surface. The coefficient of kinetic friction between the box and the surface is

0.5

. A horizontal force pulls the box at constant velocity for

10 cm

. The work done by the applied horizontal force and the frictional force are respectively

(Take g = 10 m s^{- 2})

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Physics>Mechanics>Work, Energy and Power>Work

An observer and a vehicle, both start moving together from rest (towards right) with acceleration

5 m s^{- 2}

and

2 m s^{- 2}

, respectively. There is a

2 kg

block on the floor of the vehicle and co-efficient of friction is

μ = 0.3

between their surfaces. Then the work done by frictional force on the

2 kg

block observed by the running observer, during first

2

seconds of the motion,
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The dimensions of kinetic energy is-

Important Questions on Work, Energy and Power

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