# Newton’s law worksheet

You can view detail about the Newtons laws of motion on our previous posts.Here under are the challenging objective question related to the Newton’s laws of motion .The answer are at the bottom of this worksheet.Check your ability on this topic.

1 >Newton’s first laws of motion supplies the definition of

(1) Force

(2) Velocity

(3) Acceleration

(4) Momentum

2>Newton‘s first law of motion gives the concept of -

(1) Energy

(2) Work

(3) Inertia

(4) Momentum

3>Which of the Newton’s law is related to the rate of change of linear momentum

(1) First law

(2) Second law

(3) Third law

(4) All the three laws

4> Which one of the Newton’s law is most general

(1) First law

(2) Second law

(3) Third law

(4) None

5>Which one of the Newton’s law is most closely related to conservation of linear momentum

(1) Firstlaw

(2) Second law

(3) Third law

(4) None

6>Rocket works on the principle of conservation of

(1) Mass

(2) Energy

(3) Linear momentum

(4) Angular momentum

7>When a bus starts suddenly, the upper part of sitting passenger experiences a jerk in forward direction due to

(1) Inertia of rest

(2) Inertia of motion

(3) Change in momentum

(4) Centripetal force

8>Conservation of linear momentum is equivalent to

(1) Newton’s I law

(2) Newton’s II law

(3) Newton’s III law

(4) Conservation of angular momentum

9>A cannon after firing recoils due to

(1) Conservation of energy

(2) Backward thrust of gases produced

(3) Newton’s third law of motion

(4) Newton’s first law of motion

10>When the resultant force on a body is not zero, it produces

(1) Linear acceleration

(2) Angular acceleration

(3) Constant velocity

(4) Inertia

11>On applying a constant force to a body, it moves with uniform

(1) Momentum

(2) Angular velocity

(3) Velocity

(4) Acceleration

12>The product of force and time of application of force gives

(1) Linear momentum

(2) Impulse

(3) Energy

(4) Torque

13>The impulse is equal to

(1) Linear momentum

(2) Change in linear momentum

(3) Work

(4) Torque

13>In which of the following cases force may not be required to keep the

(1) Particle going along a circular path

(2) Particle going along straight line on a rough surfaée

(3) Momentum of the particle constant

(4) Acceleration of the particle constant

14>A man getting down a running bus falls forward because

(1) Due to inertia of rest, the road is left behind and the man reaches forward

(2) Due to inertia of motion upper part of the body continues to be in motion in forward direction while feet come to rest as soon as they touch the road

(3) Road exerts a force on man in forward direction

(4) Bus exerts a force on the man in the forward direction

15>A rider on the horse-back falls when horse starts running all of the sudden because

(1) Rider is taken back

(2) Rider is suddenly afraid of falling

(3) Inertia of rest keeps the upper part of body of rest whereas lowerpart of the body moves forward with the horse

(4) No reason can be assigned.

17>An athlete runs some distance before taking a long jump because

(1) It helps to apply large force

(2) By running action and reaction force increases

(3) He gains energy to take him through long distance

(4) By running the athlete gives himself larger inertia of motion

18>While dusting a carpet we give a sudden jerk or beat it with stick because

(1) Inertia of rest keeps the dust in its position and the dirt is removed by movement of carpet away

(2) Inertia of motion removes the dirt.

(3) Jerk/beating gives acceleration to dust particle which is then removed.

(4) Jerk compensates for the force of adhesion between dirt and carpet and the dirt is removed.

19>In case of book lying on a table

(1) Action of book on table and reaction of table on book are equal and opposite and are inclined to vertical

(2) Action of book on table and reaction of table on book are equal and opposite and act perpendicular to the surfaces of contact.

(3) Action and reaction are equal but act in samc direction

(4) Action and reaction are unequal but act in different directions.

20>Which one of the following force is cdnservative.

(1) Electrostatic force

(2) Frictional force

(3) Viscous force

(4) Air resistance

21>Which one of the following force is non- conservative

(1) Gravitational force

(2) Electrostatic force

(3) Elastic force

(4) Viscous force

22>A ball of mass m is moving with speed v. The ball strikes the wall and rebounds with same speed v. The change in momentum is

(1)mv

(2) 2 mv

(3) -2mv

(4) zero

23>A passenger in a moving train tosses a coin.If the coin falls behind him,the train must be moving

(1) With an acceleration

(2) With a uniform speed

(3) With a deceleration

(4) Any of the above

24>A boy sitting on the top bench in the compartment of a train which is just going to stop a railway station ,drops an apple aiming at the open hand of his brother sitting vertically below his hand at a distance of 2m.The apple will fall

(1) Precisely on the hand of his brother

(2) Slightly away the hand of his brother in the direction of motion of the train

(3) Slightly away from the hand of the brother in the direction opposite to the direction of motion of the train.

(4) None of the above

25> A ball hangs from string railway car moving along ta horizontal track. The string is observed to be inclined towards the rear of the car, making a constant angle with the vertical. It shows that the car is

(1) Moving with uniform acceleration.

(2) Moving with uniform velocity.

(3) Moving with uniform retardation.

(4) Moving with increasing acceleration.

26>A plumb line is suspended from the roof of a rail road car. When the car is moving on a circular track, the plump line inclines

(1) Forward

(2) Rareward

(3) Towards the centre of path

(4) Away from the centre of path.

27>A plumb line suspended from the roof a carriage moving with an acceleration ‘a’ inclines at an angle $\theta$ with the vertical, then

(1) a = g tan $\theta$

(2) a = g sin $\theta$

(3) a = g cot $\theta$

(4) a =gcos $\theta$

28> Drums of oil are carried in a truck. If constant acceleration is applied on the truck, the surface of the oil in the drum will

(1) Remain unaffected

(2) Rise towards forward direction

(3) Rise towards backward direction

(4) Nothing is certain

29>A stretching force of 1000 N is applied at one end of a spring balance and an equal stretching force is applied at the other end at the same time. The reading of the balance will be

(1) 0 N

(2) 500 N

(3) 1000 N

(4) 2000 N

30>A spring obeying Hook’s law has a force constant K. Now the spring is cut in 2 equal parts, the force constant of each part will be

(1) K

(2) K\2

(3) 2 K

(4) zero

31>Two springs each of force constant K are connected end to end (in series) ; the force constant of combination will be

(1) K

(2) K\2

(3) 2 K

(4) zero

32>Two masses A and B each of mass M are connect together by a massless spring. A force F acts on the mass B as shown in fig. At the instant shown the mass A has acceleration a.What is the acceleration of mass B ?

(1)  $\dfrac{F}{M} - a$

(2) a

(3) -a

(4)  $\dfrac{F}{M}$

33>A boy of mass 40 kg is hanging from the horizontal branch of a tree. The tension in his arms is maximum when angle between the arms is

(1) 0°

(2) 60°

(3) 90°

(4) 120°

34>A block of mass M is pulled along a horizontal frictionless surface by a rope of mass m. If a force F is applied at one end of the rope, the force which the rope exerts on the block is

(1) $\dfrac{Fm}{M+m}$

(2) $\dfrac{FM}{M+m}$

(3) F

(4) $\dfrac{F}{2}$

35>A string of length L and mass M is lying on a horizontal table. A force F is applied at one of its ends. Tension in the string at a distance x from the end at which force is applied is

(1) Zero

(2) $\dfrac{FX}{l}$

(3) $\dfrac{F(l - x )}{L}$

(4) F

36>A chain of mass M and length L is kept vertical by connecting its one end to a rigid support. The tension in the chain at a distance y from the rigid support is

(1) Mg

(2) $\dfrac{Mg}{L - y}$

(3) $\dfrac{Mgy}{L}$

(4) $\dfrac{Mgl}{L - y}$

37>Two blocks A and B are connected by a uniform rope of mass 1 kg. Masses of blocks A and B are 2 kg and 4 kg respectively. The system is suspended vertically as shown in fig. The tension at mid point of the rope is

(1) 5 kg wt

(2) 3 kg wt

(3) 2.5 kg wt

(4) 4.5 kg wt

38>Fig. represents two masses M1 and M2 connected by an ideal string as shown in fig. The string passes over a pulley such that mass M2 is on the table and mass M1 hangs vertically. If left free, the acceleration of M2 will be

(1) g

(2) $\dfrac{M1 g}{M1 + M2}$

(3) $\dfrac{M2 g}{M1 + M2}$

(4) $\dfrac{M1}{M2}$

39>Two bodies of masses 4 kg and 5 kg are arranged in two positions as shown in fig. If the pulley and table are perfectly smooth, the acceleration of 5 kg body in cases (a) and (b) will be

(1) $g and \dfrac{5}{9} g$

(2) $\dfrac{4}{9}g and \dfrac{1}{9} g$

(3) $\dfrac{g}{5} and \dfrac{g}{5}$

(4) $\dfrac{5}{9} and \dfrac{1}{9} g$

40>Two blocks each of mass M are resting on a frictionless inclined plane as shown in fig.

Then

(1) The block A moves down the plate.

(2) The block B moves down the plane.

(3) Both the block remain at rest.

(4) Both the blocks move down the plate.

41> A force time graph for the motion of a body is shown in fig. The change in linear momentum between 0 and 6 seconds is

(1) Zero

(2) $+ \pi N - s$

(3) $- \pi N - s$

(4) $2 \pi N - s$

42> The pulley arrangement of figs. (a) and (b) are identical.The mass of connecting rope is neglgible.In fig (a) the mass is lifted up by

attaching a mass 3m to the other end of the rope. In fig. (b) mass m is lifted up by pulling the other end with a constant downward force F = 3mg. If the accelerations of mass m in fig. (a) and (b) are a1 and a2 respectively then the

ratio $\dfrac{a_2}{a_1}$ is

(1) 1

(2) 2

(3) 3

(4) 4

43> Two identical spheres A and B are connected by an ideal string passing over a smooth ideal pulley. Initially both spheres A and B are at rest. Now the sphere A is given a velocity v vertically downwards. Immediately after A strikes the table

(1) Both A and B are at rest

(2) A moves up and B moves down with equal speeds.

(3) B moves up and A remains at rest

(4) A and B both move up with the same speed

44>Three blocks A, B and C weighing 5 kg, I0 kg and 15 kg respectively are connected with inextensible strings as shown in fig. If force F = 60 N is applied on block C (fig) then the tension T1 in the rope connecting A and B is

(1) 5N

(2) 10 N

(3) 30N

(4) 60 N

45>A body of mass 2 kg is sliding with a constant velocity of 4 m/s on a frictionless horizontal table. The force required to keep the body moving with the same velocity is

(1) 8 N

(2) Zero N

(3) 32 N

(4) 0.5 N

46>A body of mass 2 kg is sliding with a constant velocity of 4 m/s on a frictionless horizontal table. The force exerted by the body on the table is

(1)    Zero

(2)    2 N

(3)    19.6

(4)    8 N

47>A 5 kg weight is accelerated from rest to 60 m/s in 2 seconds. The force acting on the body is

(1) 30 N

(2) 300 N

(3) 600 N

(4) 150 N

48>Gravel is dropped into a conveyer belt at the rate of 0.5 kg/s. The extra force required to keep the belt moving at 2 m/s (in Newton) is

(1) 1

(2) 2

(3) 0.5

(4) 4

49>A satellite in force free space sweeps stationary

interplanetary dust at the rate of $\dfrac{dM}{dt} = \alpha v$. The

acceleration of satellite is

(1)    $- \dfrac{2 \alpha v^2}{M}$

(2)    $- \dfrac{ \alpha v^2}{M}$

(3)    $- \dfrac{\alpha v^2}{2M}$

(4)    $- \alpha v^2$

50>A rocket is ejecting 1 kg of gases per second at the velocity of 2 km/s. The accelerating force

on the rocket is

(1) 2 N

(2) 20 N

(3) 2,000 N

(4) 20,000 N

51>A machine gun is mounted on a 2000 kg car on a horizontal frictionless surface. At some instant the gun fires bullets of mass 10 g with a velocity 500 m/s with respect to the car. If the number of bullets fired per second is 10, the acceleration of the car will be

(1)    0.025 $m/s^2$

(2)    0.25 $m/s^2$

(3)    2.5 $m/s^2$

(4)    500 $m/s^2$

52>A jet of water with area of cross-section 3$cm^2$ strikes a wall at an angle $\theta = 60^o$ to the normal and rebounds elastically from the wall with the same speed. If the speed of water in the jet is 12 m/s, then the force acting on the wall is

(1)    $4.31 \times 10^{-1} N$

(2)    $4.32 \times 10^{-2} N$

(3)    $4.32 \times 10^{-3} N$

(4)    4.32 N

53>You are marooned on a frictionless horizontal plane and can’t exert any horizontal force by pushing against the surface. How can you get off

(1) By jumping

(2) By running on the plane

(3) By rolling your body on the surface

(4) By sneezing or spitting.

54>A $U^{223}$ nucleus at rest decays by emitting an alpha-particle with a speed of v m/s. The recoil speed of residual nucleus in m/s is

(1)    $- v \times \dfrac{4}{234}$

(2)    $- \dfrac{v}{4}$

(3)    $-v \times \dfrac{4}{238}$

(4)    $v \dfrac{4}{238}$

55>A ball of mass 0.5 kg moving with a velocity of 2 m/s strikes a wall normally and bounces back with the same speed. If the time of contact between the ball and the wall is 1 millisecond the average force exerted by the wall on the
ball is

(1) 125 N

(2) I000 N

(3) 2000 N

(4) 5000 N

56>Two solid balls A and B having masses 200 g and 400 g respectively are moving in opposite directions with velocity of A equal to 0.3 m/s, After collision the two balls come to rest, when
the velocity of B is

(1) 0.1 m/s

(2) 1.5 m/s

(3) – 0.15 m/s

(4) Zero

57>A rocket has mass 1000 kg and fuel 900 kg. It ejects fuel at the rate of 1kg/s with an exhaust velocity of 2 km/s relative to rocket. The maximum velocity attained by rocket is

(1) 4.6 km/s

(2) 2.3 km/s

(3) 2 km/s

(4) 4.6 $\log_{10} \dfrac{10}{9} km/s$

58>If the tension in the cable of 1000 kg elevator is 1000 kg wt, the elevator is 1000kg wt, the elevator

(1) Is accelerating upward

(2) Is accelerating downward

(3) May be at rest or accelerating

(4) May be at rest or in uniform motion.

59>A man is standing in a lift accelerating upward, then apparent weight of man

(1) Is equal to actual weight.

(2) than the actual weight.

(3) Is less than the actual weight.

(4) Is-more than his actual weight at equator and less than at poles .

60>A boy of weight 60 kg wt is standing in a lift.If the lift begins to move up -with a uniform
speed 4.9 m/s , the apparent weight of boy is

(1) 60kg wt

(2) 90 kg wt

(3) 30 kg wt

(4) zero

61> In Q. 60, if the lift moves upward with constant acceleration $4.9 m/s^2$, the apparent weight of boy is

(1) 60 kg wt

(2) 90 kg wt

(3) 30 kg wt

(4) Zero

62>In Q. 60, if the lift moves downward with constant acceleration $4.9 m/s^2$, the apparent weight of boy is

(1) 60 kg wt

(2) 90 kg wt

(3) 30 kg wt

(4) Zero

63>In Q. 60, the lift going upward with a uniform velocity of 4.9 m/s slows down and stops in 2 seconds, then the apparent weight of the boy during the slow-down process is

(1) 60 kg wt

(2) 75 kg wt

(3) 90 kg wt

(4) 45 kg wt

64>A lift of mass 1000 kg starts moving from rest in the upward direction. The figure shows variation of speed of lift. If $T_1 , T_2 , T_3$ represent the tension in the cable supporting the lift, when moving with uniform acceleration, uniform velocity and uniform retardation respectively, then $g = 10 m/s^2$

(1)    $T_1 : T_2 : T_3 = 1 : 1 : 1$

(2)    $T_1 : T_2 : T_3 = 6 : 5 : 3$

(3)    $T_1 : T_2 : T_3 = 3 : 5 : 6$

(4)    $T_1 : T_2 : T_3 = 6 : 5 : 6$

65>A bullet is fired by a light rifle and the other by a heavy rifle by the same force. Which rifle will cause more injury to the shoulder

(1) Light rifle

(2) Heavy rifle

(3) Both will cause the same journey

(4) Enough information is not available.

66>A bullet of mass ‘a’ and velocity ‘b’ is fired into a large block of wood of mass ‘c’. The final velocity of the system is

(1)    $( a ) \dfrac{b}{a + b}$

(2)    $( a ) \dfrac{a + b}{c}$

(3)    $( b ) \dfrac{a}{a + c}$

(4)    $( b ) \dfrac{a + c}{a}$

67>A massless string passes around a frictionless pulley whose axis is horizontal. A monkey holds on one end of a string and a body with the same mass as the monkey is attached to the other end. Now monkey starts climbing upward with acceleration, then the motion of the other
body will be

(1) Downward acceleration a

(2) Upward acceleration a

(3) Upward acceleration a/2

(4) Downward acceleration a/2

68>A body weighs 8 g when placed in one pan and 18 g when placed in the other pan of a false balance. If the beam is horizontal when both the pans are empty, the true weight of the body is

(1)12 g

(2) 13 g

(3) 15 g

(4) 26 g

69>A boy having a mass of 60 kg holds in hands a school bag of weight 40 N. With what force the floor will push up on his feet ? (g = 10)

(1)    100 N

(2)    600 N

(3)    640 N

(4)    64 N

70>What is the force required to lift a 100 kg load, with the pulley system shown in fig. Pulleys are weightless and frictionless and string is ideal.

(1)    100 N

(2)    600N

(3)    640 N

(4)    64 N

71>A 20 kg crate hangs at the end of a long rope. Find its acceleration when the tension in the rope is 150 N

(1)    $2.7 m/s^2 upward$

(2)    $2.7 m/s^2 downward$

(3)    $2.3 m/s^2 upward$

(4)    $\dfrac{13}{15} m/s^2 upward$

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