MCQ Questions for Class 11 Physics Chapter 5 Laws of Motion with Answers
Solving the Laws of Motion Multiple Choice Questions of Class 11 Physics Chapter 5 MCQ can be of extreme help as you will be aware of all the concepts. These MCQ Questions on Laws of Motion Class 11 with answers pave for a quick revision of the Chapter thereby helping you to enhance subject knowledge. Have a glance at the MCQ of Chapter 5 Physics Class 11 and cross-check your answers during preparation.
Question 1.
A spring balance is attached to the ceiling of a lift. A man hangs his bag on the spring and the spring reads 49 N, when the lift is stationary. If the lift moves downwards with an acceleration of 5 m/s, the reading of the spring balance will be
(a) 15 N
(b) 24 N
(c) 49 N
(d) 74 N
Answer
Answer: (b) 24 N
Question 2.
Two forces 6 N and 8 N act at a point O. If the angle between the lines of action of the force is 90°, then their resultant is
(a) 14 N
(b) 12 N
(c) 10 N
(d) 48 N
Answer
Answer: (c) 10 N
Question 3.
A body of mass 15 kg moving with a velocity of 10 m/s has its velocity reduced to 6 m/s in two seconds. The force that produced this change in velocity is
(a) 60 N
(b) 30 N
(c) 45 N
(d) 20 N
Answer
Answer: (b) 30 N
Question 4.
The frame of reference attached to a satellite of the earth is
(a) an inertial frame
(b) an absolute frame at rest with respect to the stars
(c) a non – inertial frame
(d) a gravitational frame
Answer
Answer: (c) a non – inertial frame
Question 5.
A machine gun fires a bullet of mass 40 g with a velocity of 1200 ms-1. The man holding it can exert a maximum force on 144 N on the gum. How many bullets can he fire per second at the most?
(a) one
(b) four
(c) two
(d) three
Answer
Answer: (d) three
Question 6.
A block of mass M is placed on a flat surface. A force is applied to move it parallel to the surface. The frictional force f developed is proportional to the
(a) square of the mass of the body
(b) mass of the body
(c) reciprocal of the mass of the body
(d) reciprocal of the square of the body
Answer
Answer: (b) mass of the body
Question 7.
A passenger in a moving bus is thrown forward when the bus is suddenly stopped. This is explained
(a) by Newtons first law
(b) by Newtons second law
(c) by Newtons third law
(d) by the principle of conservation of momentum
Answer
Answer: (a) by Newtons first law
Question 8.
A rocket with a lift-off mass of 3.5 × 10 kg is blasted upwards with an acceleration of 10 m/s². The initial thrust of the blast is (take g = 10 m/s²)
(a) 1.75 × 105N
(b) 3.5 × 105N
(c) 7.0 × 105N
(d) 14 .0 × 105N
Answer
Answer: (c) 7.0 × 105N
Projectile motion calculator finds the initial and final velocity, initial and final height, maximum height, horizontal distance
Question 9.
A gun of mass 1000 kg fires a projectile of mass 1 kg with a horizontal velocity of 100 m/s. The velocity of recoil of the gun in the horizontal direction is
(a) 5 m/s
(b) 0.1 m/s
(c) 15 m/s
(d) 20 m/s
Answer
Answer: (b) 0.1 m/s
Question 10.
A body is sliding down a rough inclined plane which makes an angle of 30 degree with the horizontal. If the co-efficient of friction is 0.26, the acceleration in m/s² is
(a) 1.95
(b) 2.78
(c) 3.47
(d) 4.6
Answer
Answer: (b) 2.78
Question 11.
A block of mass M is placed on a flat surface. A force is applied to move it parallel to the surface. The frictional force f developed is proportional to the
(a) square of the mass of the body
(b) mass of the body
(c) reciprocal of the mass of the body
(d) reciprocal of the square of the body
Answer
Answer: (b) mass of the body
Question 12.
A force of 12 N acts on a body of mass 2 kg. The acceleration produced on the body is
(a) 24 m/s²
(b) 6 m/s²
(c) 14 m/s²
(d) 10 m/s²
Answer
Answer: (b) 6 m/s²
Question 13.
The mass of a body is 2 kg. It weight is
(a) 19.6 N
(b) 20 N
(c) 30 N
(d) 40 N
Answer
Answer: (a) 19.6 N
Question 14.
A gun of mass 1000 kg fires a projectile of mass 1 kg with a horizontal velocity of 100 m/s. The velocity of recoil of the gun in the horizontal direction is
(a) 5 m/s
(b) 0 .1 m/s
(c) 15 m/s
(d) 20 m/s
Answer
Answer: (b) 0 .1 m/s
Question 15.
A body of mass 15 kg moving with a velocity of 10 m/s has its velocity reduced to 6 m/s in two seconds. The force that produced this change in velocity is
(a) 60 N
(b) 30 N
(c) 45 N
(d) 20 N
Answer
Answer: (b) 30 N
Question 16.
A heavy uniform chain lies on horizontal table top. If the coefficient of friction between the chain and the table surface is 0.25, then the maximum fraction of the length of the chain that can hang over the edge of the table is
(a) 20%
(b) 25%
(c) 30%
(d) 35%
Answer
Answer: (a) 20%
Question 17.
A body is sliding down a rough inclined plane which makes an angle of 30 degree with the horizontal. If the co-efficient of friction is 0.26, the acceleration in m/s² is
(a) 1.95
(b) 2.78
(c) 3.47
(d) 4.6
Answer
Answer: (b) 2.78
Question 18.
The mass of a body which is equal to the ratio of the force acting on a body to the acceleration produced in the body is
(a) the gravitational mass
(b) the electromagnetic mass
(c) the internal mass
(d) the inertial mass
Answer
Answer: (d) the inertial mass
Question 19.
A machine gun fires a bullet of mass 40 g with a velocity of 1200 ms-1. The man holding it can exert a maximum force on 144 N on the gum. How many bullets can he fire per second at the most?
(a) one
(b) four
(c) two
(d) three
Answer
Answer: (d) three
Question 20.
A passenger in a moving bus is thrown forward when the bus is suddenly stopped. This is explained
(a) by Newtons first law
(b) by Newtons second law
(c) by Newtons third law
(d) by the principle of conservation of momentum
Answer
Answer: (a) by Newtons first law
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