#### 11th Standard Physics Laws of Motion English Medium Free Online Test One Mark Questions with Answer Key 2020 - 2021

11th Standard

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Physics

Time : 00:20:00 Hrs
Total Marks : 20

20 x 1 = 20
1. 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

2. 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

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

4. Action and reaction

(a)

act on two different objects

(b)

have opposite direction

(c)

have equal magnitude

(d)

all of these

5. 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)

$\frac { W }{ 2 }$

6. 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)

$\frac { { F }_{ 2 } }{ m }$

7. Momentum is closely related to

(a)

Force

(b)

Impulse

(c)

Velocity

(d)

K.E

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

(a)

Velocity

(b)

(c)

Mass of the particle

(d)

a&c

9. 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

10. 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

11. 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

12. 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

13. 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

14. 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

15. Third law of Newton explains the concept of:

(a)

inertia

(b)

momentum

(c)

torque

(d)

nature of the force

16. 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)

17. 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

18. 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

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

(a)

halved

(b)

tripled

(c)

doubled

(d)

not changed

20. The condition for skidding is

(a)

tanθ=μ

(b)

tanθ < μ

(c)

tanθ > μ

(d)

tanθ = 0