# Laws of Motion VBQs Class 11 Physics

VBQs Laws of Motion Class 11 Physics with solutions has been provided below for standard students. We have provided chapter wise VBQ for Class 11 Physics with solutions. The following Laws of Motion Class 11 Physics value based questions with answers will come in your exams. Students should understand the concepts and learn the solved cased based VBQs provided below. This will help you to get better marks in class 11 examinations.

## Laws of Motion VBQs Class 11 Physics

Question. Two blocks of masses 5 kg and 4 kg are connected by a massless spring as shown in figure. If the instantaneous acceleration of the 5 kg body is 4 m/s2 towards right, then instantaneous acceleration of the 4 kg body will be    (Image 11)
(a) 0.5 m/s2 to right
(b) 0.5 m/s2 to left
(c) 5 m/s2 to right
(d) 5 m/s2 to left

B

Question. A hydrogen balloon is fixed by a string at the bottom of a closed car as shown in figure. If the car accelerates horizontally with acceleration a = g, then the balloon will       (Image 11)
(a) Shift to right through 45°
(b) Shift to left through 45°
(c) Remain vertical
(d) Shift to left through any angle

A

Question. A motor delivers water of density ρ at a constant speed v through a pipe of area A. Force exerted by motor on water is
(a) Av2ρ
(b) Avρ
(c) Av3ρ
(d) Aρ2v

A

Question. A light string passes over a pulley as shown in figure.
A man of mass 5 kg climbs up the rope. If tension in the rope is equal to 80 N, what will be the acceleration of man in upward direction? (g = 10 m/s2)
(a) 4 ms–2
(b) 8 ms–2
(c) 6 ms–2
(d) 2 ms–2

C

Question. Two blocks having masses 10 kg and 5 kg are placed on smooth surface, having co-efficient of friction between the surfaces of block as shown in figure. Find the acceleration of mass 10 kg.   (Image 12)
(a) 0 ms–2
(b) 3.75 ms–2
(c) 0.1 ms–2
(d) 7.5 ms–2

D

Question. In the figure shown below, if the inclined plane has coeff. of friction, μ = 0.3, then 0.2 kg mass will move down with an acceleration    (Image 12)
(a) 0.2 ms–2
(b) 0.4 ms–2
(c) 2.4 ms–2
(d) 0.8 ms–2

C

Question. In the arrangement shown, the rope is light and inextensible and pulley is light and smooth. The normal reaction between the 50 kg block and ground is (g =10 m/s2)   (Image 12)
(a) 200 N
(b) 300 N
(c) 500 N
(d) Zero

B

Question. A car is moving at a constant velocity 20 m/s on a straight road xy. P is an observer at a perpendicular distance 50 m from the cross O. The angular velocity of the car with respect to the observer at the instant shown is  (Image 11)

B

Question. A man slides down on a rough vertical pole with an acceleration equal to one-fifth of acceleration due to gravity (g). The frictional force between man and pole is (w = weight of man)
(a) w/5
(b) 3w/s
(c) 4w/5
(d) w/2

C

Question. A uniform rope of mass M and length L is hanging from the ceiling inside a lift going vertically upward with a constant acceleration a. The tension in the rope at a distance x (x < L) below its upper end is     (Image 13)

B

Question. A wedge and block having masses 10 kg and 2 kg respectively shown in figure. A force F is applied on the wedge towards left so that block falls freely. At time of falling, contact force between wedge and block is     (Image 15)
(a) 2gcos30°
(b) 2gcos60°
(c) gsin30°
(d) Zero

D

Question. Two inclined frictionless tracks, one gradual and the other step meet at A from where two stones are allowed to slide down from rest one on each track (figure). Then mark correct option     (Image 15)
(a) Both stones reach the bottom at same speed
(b) They will reach the bottom at different time
(c) Stone (b) will reach bottom first
(d) All of these

D

Question. Force-time graph of a body is as shown in figure.
The body starts with initial velocity 10 m/s at t = 0.
Change in momentum of the body in the interval 0 to 20 s is   (Image 11)
(a) 1000 Ns
(b) 2000 Ns
(c) 100 Ns
(d) 500 Ns

A

Question. A body m of mass 10 kg is placed on an inclined plank of mass M of 50 kg as shown in figure. If 10 kg mass falls freely, then contact force between M and m will be (Image 12)
(a) 100 N
(b) 100√3
(c)100/√3
(d) Zero

D

Question. A body of mass m is suspended by a string of length l. The string is fixed at the other end and the body moves in a horizontal circle such that the string makes angle θ with vertical. The time period of its circular motion is (Image 12)

C

Question. Two block A & B are placed as in figure (mA < mB).
A force F acts on block A towards left. Friction force acting on B due to A block is in direction [μ is friction coefficient between A & B]    (Image 15)
(a) Toward right
(b) Towards left
(c) Towards up
(d) Towards down

B

Question. A circular road of radius 40 m is banked at an angle of 45° with horizontal. The speed of vehicle on the road at which effect of friction neglected is
(a) 40 km/h
(b) 72 km/h
(c) 20 km/h
(d) 80 km/h

B

Question. Two blocks A and B of mass 2 kg and 3 kg are kept in contact with each other on a rough inclined plane as shown in figure. Coefficient of static fraction of block A and block B with plane are 0.3 and 0.4 respectively. If both are released simultaneously, then reaction between A and B is  (Image 12)
(a) 10 N
(b) 5 N
(c) 15 N
(d) Zero

D

Question. Block B is pulled by a horizontal force F. Maximum acceleration of the blocks for which A will not slip over B is    (Image 12)
(a) 5 m/s2
(b) 10 m/s2
(c) 2 m/s2
(d) 8 m/s2

A

Question. Two weights W1 and W2 are suspended from the ends of a light string passing over a smooth fixed pulley. The net force on the pulley will be    (Image 13)

D

Question. A small block of mass m is placed on a rough fixed wedge of mass M as shown. If the coefficient of friction between m and M is μ and θ is less than tan–1(μ), then the force exerted by M on m will be   (Image 13)
(a) mg cosθ
(b) mg sinθ
(c) μmg cosθ
(d) mg

D

Question. A hemispherical bowl of radius R is rotating about its own axis (vertical) with an angular velocity ω. A particle of mass 10–2 kg on the frictionless inner surface of bowl is also rotating with the same angular velocity.
The particle is at a height h from botton of bowl. The condition to be satisfied to have a non-zero value of h is    (Image 13)

A

Question. Pulley and string shown in the figure are massless and frictionless. Tension in the string will be   (Image 13)
(a) 20 N
(b) 18 N
(c) 16 N
(d) 12 N

B

Question. Figure shows two blocks of masses 5 kg and 20 kg connected by a light, inextensible string passing over a smooth pulley of mass 10 kg. An upward pulling force is applied on the pulley as shown. The reaction force between 5 kg block and ground is   (Image 14)
(a) 50 N
(b) 40 N
(c) 10 N
(d) Zero

B

Question. Two masses m1 and m2 are connected by massless string as shown in figure. If both are moving in a circle with same angular speed and T1 and T2 are tensions in the strings, then     (Image 15)
(a) T1 < T2
(b) T2 = T1
(c) T1 > T2
(d) T2 > T1 if m2 > m1

C

Question. A car is accelerating horizontally with acceleration a towards left. A bob of mass m suspended from its roof by a string. The angle made by string from vertical at equilibrium is    (Image 15)

C

Question. On a highway at a horizontal sharp turn of radius 20 m a sign board indicate that the maximum speed of vehicles will be 20 m/s. The minimum coefficient of friction between tyres of vehicle and road is
(a) 0.02
(b) 0.2
(c) 2
(d) 20

C

Question. Two blocks A and B are connected by a massless string. A and B are kept on a horizontal frictionless floor. When B is pulled to right by a force horizontally, tension in the string is T1. When A is pulled to left by the same force horizontally, tension in the string is T2. The ratio T1/T2 is.   (Image 11)

(a) 1 : 1
(b) 2 : 3
(c) 4 : 9
(d) 5 : 3

B

Question. A sphere is placed between two walls. How many normal reactions are acting on the sphere? (Image 11)
(a) 1
(b) 3
(c) 2
(d) 4

A

Question. A block of mass 2 kg is kept on horizontal surface with coefficient of friction as indicated in figure. A horizontal time varying force F = (2 + t)N starts acting on the block at t = 0. Find the time after which the block begins to slide (g = 10 ms–2)   (Image 14)
(a) 2 s
(b) 8 s
(c) 10 s
(d) 16 s

C

Question. Accelerations of the blocks m1 and m2 in the given figure are (m1 = 5 Kg, m2 = 10 Kg)    (Image 15)
(a) 1 m/s2, 0
(b) 2 m/s2, 2/3 m/s2
(c) 2/3 m/s2 , 1 m/s2
(d) 2/3 m/s2 , 2/3 m/s2

D

Question. Three masses M1, M2, M3 of masses 1 kg, 3 kg and 3 kg respectively are attached as shown in figure.     (Image 14)
Correct relation between T, T1 and T2 is
(a) T < T1 < T2
(b) T > T1 > T2
(c) T = T1 > T2
(d) T1 > T2 > T

B

Question. In given figure a body of mass 10 kg placed on a rough horizontal surface of coefficient friction of      (Image 14)
If a horizontal force F = 10 N applied on it, then the value of acceleration of the body will be
(a) 1 m/s2
(b) 0.8 m/s2
(c) Zero
(d) 1.2 m/s2

C

Question. A block of mass 1 kg is placed on a rough horizontal surface. Find acceleration of body if horizontal force F = 10 N applied on it. (Initially block is at rest)     (Image 14)
(a) 1 m/s2
(b) 8 m/s2
(c) Zero
(d) 1.2 m/s2

B

Question. Free body diagram of a block of mass m at rest on an unlevelled ground as shown in figure is     (Image 14)

C

Question. A block of mass 10 kg is at rest on a rough surface coefficient of friction μ = 0.6, then downward acceleration of body is     (Image 15)
(a) gsin30°
(b) gcos30°
(c) g/sin30°
(d) Zero

C

Question. A block of mass m kg rest on a fixed rough wedge of inclination 60° having mass M kg. Then minimum value of coefficient of friction between block and wedge is   (Image 15)
(a) mg/cos60°
(b) gcot60°
(c) √3
(d) 1/√3

B

Question. Linear momentum of a body of mass 5 kg is given by (Image 11)
(a) −1 ms−2 iˆ
(b) 1 ms−2 iˆ
(c) −1 ms−2 jˆ
(d) 1 ms−2 jˆ

B

Question. N small balls each of mass m hit a surface each second elastically with velocity u. The force experienced by the surface is
(a) Nmu
(b) Nmu /2
(c) 2Nmu
(d) 4Nmu

C

Question. If in the given figure M1 = 1 kg; M2 = 2 kg; M3 = 3 kg, then    (Image 14)  the acceleration of mass M2 will be   B
(a) 2 m/s2
(b) 1 m/s2
(c) 6 m/s2
(d) 3 m/s2

B

Question. If a nucleus of mass m eject an α – particle of mass m/59with velocity u, then recoil speed of product nucleus is
(a) u/59
(b) 58 u/59
(c) u/ 58
(d) 59u/58

C

Question. A bullet of mass 10 g fired by a gun at speed 150 m/s. It comes to rest in 0.01 s after collision with a wall, then average force applied by the wall on it is
(a) 15 N
(b) 30 N
(c) 150 N
(d) 1500 N