A book is at rest on the table which exerts a normal force on the book. If this force is considered as reaction force, what is the action force according to Newton's third law?

(a)

Gravitational force exerted by Earth on the book

(b)

Gravitational force exerted by the book on Earth

(c)

Normal force exerted by the book on the table

(d)

None of the above

Two blocks of masses m and 2m are placed on a smooth horizontal surface as shown. In the first case only a force F₁ is applied from the left. Later only a force F₂ is applied from the right. If the force acting at the interface of the two blocks in the two cases is same, then F₁ :F₂ is

(a)

1:1

(b)

1:2

(c)

2:1

(d)

1:3

When an object is at rest on the inclined rough surface ____________.

(a)

static and kinetic frictions acting on the object is zero

(b)

static friction is zero but kinetic friction is not zero

(c)

static friction is not zero and kinetic friction is zero

(d)

static and kinetic frictions are not zero

Action and reaction ___________

(a)

act on two different objects

(b)

have opposite direction

(c)

have equal magnitude

(d)

all of these

A heavy iron rod of weight W is having its one end on the ground and the other on the shoulder of a man. The rod makes an angle ፀ with the horizontal. What is the weight experienced by the man?

(a)

W sin ፀ

(b)

W cos ፀ

(c)

W

(d)

\(\frac { W }{ 2 } \)

Three forces F₂, F₂ & F₃ are acting on a particle of mass m such that F₂ & F₃ are mutually perpendicular, then the particle remains stationary. If the force F₁ is now removed, then the acceleration of the particle is _____________.

(a)

\(\frac { { F }_{ 1 } }{ m } \)

(b)

\(\frac { { F }_{ 2 }{ F }_{ 3 } }{ mF } \)

(c)

\(\frac { { F }_{ 2 }-{ F }_{ 3 } }{ m } \)

(d)

\(\frac { { F }_{ 2 } }{ m } \)

Momentum is closely related to _______________.

(a)

Force

(b)

Impulse

(c)

Velocity

(d)

K.E

A particle revolves round a circular pattern. The acceleration of the particle is inversely proportional to ______________

(a)

Velocity

(b)

Radius

(c)

Mass of the particle

(d)

a&c

A machine gun fires bullets each of mass 2 g with a velocity of 20 ms^-1 by an exerting constant force of 10 g weight. Then the number of bullets fired per second is ______________.

(a)

n = 5

(b)

n = 15

(c)

n = 10

(d)

n = 4

A machine gun has mass 15 kg. It fires 15 g bullet at the rate of 200 bullets per minutes with a speed of 150 m/s. Then the recoil velocity of the gun is ____________.

(a)

20 ms^-1

(b)

15 ms^-1

(c)

150 ms^-1

(d)

0.2 ms^-1

No force is required for ____________.

(a)

an object moving in circular motion.

(b)

an object moving in straight line with constant velocity.

(c)

an object moving with constant acceleration.

(d)

an object moving in elliptical pattern

Inertia is that property of a body by virtue of which the body is ____________.

(a)

unable to change by itself the state o frest

(b)

unable to change by itself the state of uniform motion

(c)

unable to change by itself the direction of motion

(d)

unable to change by itself the state of rest and ofunifonn linear motion

A jet plane moves up in air because ____________.

(a)

the gravity does not act on bodies moving with high speeds

(b)

the thrust of the jet compensates for the force of gravity

(c)

the flow of air around the wings causes an upward force, which compensates for the force of gravity

(d)

the weight of air whose volume is equal to the volume of the plane is more than the weight of the plane

Which law gives a method of measuring force?

(a)

Newton's first law of motion

(b)

Newton's second law of motion

(c)

Newton's third law of motion

(d)

None

Third law of Newton explains the concept of _____________.

(a)

inertia

(b)

momentum

(c)

torque

(d)

nature of the force

A book lying on the table continues in its state of rest unless an external force acts on it. It is due to _____________.

(a)

inertia of rest

(b)

inertia of motion

(c)

inertia of direction

(d)

both (b) and (c)

A large force is acting on a body for a short time. The impulse imparted is equal to the change in ________________

(a)

acceleration

(b)

momentum

(c)

energy

(d)

velocity

According to the conservation of linear momentum ________________.

(a)

momentum before impact = momentum after impact

(b)

momentum before impact > momentum after impact

(c)

momemtum before impact < momentum after impact

(d)

momentum before impact is inversely proportional to momentum after impact

If the normal force is doubled, then coefficient of friction is ______________.

(a)

halved

(b)

tripled

(c)

doubled

(d)

not changed

The condition for skidding is _______________.

(a)

tanθ=μ

(b)

tanθ < μ

(c)

tanθ > μ

(d)

tanθ = 0