# MCQ Questions for Class 11 Physics Chapter 5 Laws of Motion with Answers

As we know that preparing for NEET or any competitive exams is never an easy task. But you can reduce this difficulty by buying some good books and practice papers. Here we are providing MCQ on Laws Of Motion class 11 that will help you to understand the basic concepts of Laws Of Motion and even help you get a good score with sufficient practice questions on each topic.

Here, we tried to simplify the complexities of some of the important topics in the form of Laws of Motion Class 11 MCQ questions and answers so that preparation becomes easy for you. Nowadays varieties of conceptual questions have been asked in the examinations based on basic concepts of Laws Of Motion class 11 pdf phenomena are more important for all competitive exams.

## Important points to remember about Laws Of Motion class 11

•  force is required to put a stationary body in motion or stop a moving body, and some external agency is needed to provide this force.
•  The external agency may or may not be in contact with the body.  An external force is required to keep a body in motion. When the car is in uniform motion, there is no net external force acting on it: the force by the child cancels the force ( friction)by the floor.
• The corollary is: if there were no friction,the child would not be required to apply any force to keep the toy car in uniform motion.
• The opposing forces such as friction (solids) and viscous forces (for fluids) are always present in the natural world.  If the planes are smooth, the final height of the ball is nearly the same as the initial height (a little less but never greater). In the ideal situation, when friction is absent, the final height of the ball is the same as its initial height.
• If the slope of the second plane is decreased and the experiment repeated, the ball will still reach the same height, but in doing so, it will travel a longer distance.
•  In the limiting case, when the slope of the second plane is zero (i.e. is a horizontal) the ball travels an infinite distance.
• In other words, its motion never ceases.
• first law of motion:Every body continues to be in its state of rest or of uniform motion in a straight line unless compelled by some external force to act otherwise no net force acting on the body.
•  It is incorrect to assume that a net force is needed to keep a body in uniform motion.
• To maintain a body in uniform motion, we need to apply an external force to ecounter the frictional force, so that the two forces sum up to zero net external force.
• To summarise, if the net external force is zero,a body at rest continues to remain at rest and a body in motion continues to move with a uniform velocity. This property of the body is called inertia. Inertia means ‘resistance to change’.
• A body does not change its state of rest or uniform motion, unless an external force compels it to change that state.
• Momentum of a body is defined to be the product of its mass m and velocity v, and is denoted by p:p = m v
• Momentum is clearly a vector quantity. product of mass and velocity, that is momentum.
• second law of motion expressed by Newton as follows :The rate of change of momentum of a body is directly proportional to the applied force and takes place in the direction in which the force acts.
• large force acting for a short time to produce a finite change in momentum is called an impulsive force.
• mutual forces for each pair are equal and opposite, the momentum changes cancel in pairs and the total momentum remains unchanged.This fact is known as the law of conservation of momentum .
• action-reaction pair consists of mutual forces which are always equal and opposite between two bodies. Two forces on the same body which happen to be equal and opposite can never constitute an action-reaction pair.

## Multiple Choice Questions On Laws Of Motion Class 11 pdf

1.Inertia is the property of a body linked to tendency of a body__________

a) to change the momentum

b) to resist any change in its state

c) to change its direction

d) to change its position

2.When a bus starts suddenly, the passengers are pushed back. This is an example of which of the following?

a) Newton’s first law

b) Newton’s second law

c) Newton’s third law

d) None of Newton’s laws

3. Newton’s first law is also known as _______

a) Law of rotation

b) Law of Inertia

c) Law of momentum

d) None of the option is correct

4. A passenger in a moving bus is thrown forward when the bus is suddenly stopped. This is explained by __________

a)  Newtons first law

b) Newtons second law

c) Newtons third law

d) the principle of conservation of momentum

5. 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

6. A block of wood is placed on a surface. A force is applied parallel to the surface to move the body. The frictional force  acts as ________

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

7. Choose the correct statement.

a) A body can be accelerated by frictional force

b) There can be zero friction

c) Kinetic friction is greater than rolling friction

d) Frictional force and area of contact between the two surfaces are proportional

8. Consider a man standing on the spring balance such that the reading on the spring balance is 60kg. If the man jumps out of the spring balance what will be the final reading of the spring balance?

a) Remains unchanged

b) Increases

c) Decreases

d) First increases then decrease to zero

9. Which of the following should be constant for a body to have a constant momentum?

a) Acceleration

b) Force

c) Velocity

d) All of the above

10. 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

11. 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

12. The force that produces an acceleration of 1 ms−2 in a body of the mass of 1 kg is called___________

a) slow newton

b) zero newton

c) one newton

d) two newton

14. Mass of a body (m) into acceleration (a) is equal to_________

a) Force

b) displacement

c) momentum

d) Inertia

15. When a net force act on a body, it produces acceleration in the body in the direction of the net force which is directly proportional to the net force acting on the body and inversely proportional to its mass. This statement is called_________

a) newton’s 2nd law of motion

b) newton’s 1st law of motion

c) newton’s 3rd law of motion

d) law of momentum

16. The momentum of a body of given mass is proportional to_______

a) Its colour

b) Its Shape

c) Its volume

d) Its Velocity

17. A unit of force is_______

a) Joule – m

b) Joule

c) Newton – m

d) Kg ms−2

18. Some of the leaves may get detached from a tree if we vigorously shake its branch because of___________

a) conservation of energy

b) newton’s II law of motion

c) newton’s I law of motion

d) newton’s III law of motion

19. Momentum of a body of mass 0.5 kg moving with a speed of 10 m/s is​__________

a) 2.5 kg.m/s

b) 5 kg.m/s

c) 0.5 kg.m/s

d) 50 kg.m/s

20. A mass M breaks into two pieces in the ratio 1 : 3 while at rest. If the heavier has a speed of v, the speed of the lighter is__________

(a) v

(b) 3v

(c) 1v

(d) 4v

21. A high jumper runs for a while before taking high jump so that the inertia of __________ help him in taking a long jump.

a) motion

b) shape

c) rest

d) direction

22. When an elevator cabin falls down, the cabin and all the bodies fixed in the cabin are accelerated with respect to________

a) man standing on earth

b) ceiling of elevator

c) floor of elevator

d) man standing in the cabin

23. An object will possess uniform motion as long as the______________

a) resultant force acting on it begins to decrease

b) resultant force on acting on it increases continuously

c) resultant force is right angles to its rotation

d) resultant force acting on it is zero

24. What will happen if the body at rest is made to move in a straight line and obstructed by an opposite force?

a) The body slows down

b) The body changes direction

c) The body will continue to move in the same direction with the same speed

d) All of the above

25. A car sometimes overturns while taking a turn. When it overturn, it is_____________

a) the inner wheel, which leaves the ground first

b) the outer wheel, which leaves the ground first

c) both the wheels leaves the ground simultaneously

d) either wheel, which leave the ground first

26. 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%

27. A bomb of mass 30kg at rest explodes into two pieces of masses 18kg and
12kg. The velocity of 18kg mass is 6ms–1
. The kinetic energy of the other
mass is______

a) 324 J

b) 486 J

c) 256 J

d) 524 J

28. Starting from rest, a body slides down a 45° inclined plane in twice the time it takes to slide down the same distance in the absence of friction. The
coefficient of friction between the body and the inclined plane is_________

a) 0.8

b) 0.75

c) 0.707

d) 0.5

29. A bullet is fired from a gun. The force (in N) on the bullet is given by F= 600 – 2×10⁵ t newton where t is time in second. The force becomes zero as soon as it leaves the barrel. The impulse imparted to the bullet is___________

a) 9 Ns

b) 0 Ns

c) 1.8 Ns

d) 0.9 Ns