# CBSEtips.in

## Sunday 21 February 2021

### CBSE Class 11 Physics - MCQ and Online Tests - Unit 5 - Laws of Motion

#### CBSE Class 11 Physics – MCQ and Online Tests – Unit 5 – Laws of Motion

Every year CBSE schools conducts Annual Assessment exams for 6,7,8,9,11th standards. These exams are very competitive to all the students. So our website provides online tests for all the 6,7,8,9,11th standard’s subjects. These tests are also very effective and useful for those who preparing for any competitive exams like Olympiad etc. It can boost their preparation level and confidence level by attempting these chapter wise online tests.

These online tests are based on latest CBSE syllabus. While attempting these our students can identify the weak lessons and continuously practice those lessons for attaining high marks. It also helps to revise the NCERT textbooks thoroughly.

#### CBSE Class 11 Physics – MCQ and Online Tests – Unit 5 – Laws of Motion

Question 1.
A body is sliding down a rough inclined plane which makes an angle of 30 degree with the horizontal. If the coeffcient of friction is 0.26, the acceleration in m/s² is
(a) 1.95
(b) 2.78
(c) 3.47
(d) 4.6

Question 2.
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

Question 3.
A bullet of mass 25 g moving with a velocity of 200 cm/s is stopped within 5 cm of the target. The average resistance offered by the target is
(a) 1 N
(b) 2 N
(c) 3 N
(d) 4 N

Question 4.
The force required to produce an acceleration of 2 m/s² on a mass of 2 kg is
(a) 4 N
(b) 10 N
(c) 22 N
(d) 18 N

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

Question 6.
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: (a) by Newtons first law

Question 7.
A passenger sitting in a bus moving at uniform speed, feels pushed backward whenever the bus is accelerated forward. This type of force is called
(a) Gravitational force
(b) real force
(c) fictitious force or pseudo force
(d) frictional force

Answer: (c) fictitious force or pseudo force

Question 8.
A body of mass 5 kg is travelling with a uniform velocity of 2 m/s. Its momentum is
(a) 10 kg m/s
(b) 7 kg m/s
(c) 2 .5 kg m/s
(d) 3 kg m/s

Question 9.
Inside the nucleus, two protons are held together by a force which overcomes the repulsion. This force is called
(a) gravitational force
(b) electrostatic force
(c) weak force
(d) strong force

Question 10.
A block of wood is placed on a surface. A force is applied parallel to the surface to move the body. The frictional force developed acts
(a) normal to the surface upwards
(b) normal to the surface downwards
(c) along the direction of the applied force
(d) opposite to the direction of the applied force

Answer: (d) opposite to the direction of the applied force

Question 11.
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

Question 12.
A spherical ball of mass 10-6 kg hits a wall 1000 times per second normally with a velocity of 1000 m/s and rebounds with same velocity along the initial direction. The force experienced by the wall is
(a) 1 N
(b) 4 N
(c) 2 N
(d) 8 N

Question 13.
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: (c) a non – inertial frame

Question 14.
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: (b) mass of the body

Question 15.
A block of wood is placed on a surface. A force is applied parallel to the surface to move the body. The frictional force developed acts
(a) normal to the surface upwards
(b) normal to the surface downwards
(c) along the direction of the applied force
(d) opposite to the direction of the applied force

Answer: (d) opposite to the direction of the applied force

Question 16.
A block of mass 2 kg rests on a rough inclined plane making an angle of 30 degree with the horizontal. The coefficient of static friction between he block and the plane is 0.7. The frictional force on the block is
(a) 9.8 N
(b) 0.7 × 9.8 × v3 N
(c) 9.8 × v3 N
(d) 0.7 × 9.8 N

Answer: (d) 0.7 × 9.8 N

Question 17.
A particle of mass 0.3 kg is subjected to a force F = -kx with k = 15 N/m. What will be its initial acceleration if it is released from a point 20 cm away from the origin?
(a) 15 m/s²
(b) 3 m/s²
(c) 10 m/s²
(d) 5 m/s²

Question 18.
Two bodies of masses 4 kg and 5 kg are acted upon by the same force. If the acceleration of lighter body is 2 m/s², the acceleration of heavier body is
(a) 1 m/s²
(b) 1.2 m/s²
(c) 1.6 m/s²
(d) 1.8 m/s²

Question 19.
Out of the basic forces , gravitational force
(a) ranks first in strength
(b) ranks second in strength
(c) ranks third in strength
(d) ranks fourth in strength

Answer: (d) ranks fourth in strength

Question 20.
The mass of a body is 2 kg. It weight is
(a) 19.6 N
(b) 20 N
(c) 30 N
(d) 40 N