# CBSE Class 11-Physics: Circular Motion Conceptual Questions (For CBSE, ICSE, IAS, NET, NRA 2022)

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## Multiple Choice Questions

Question1:

A small car and a big truck travel at the same speed v around the icy banked curve road. Small car which has a mass negotiates the curve without slipping. Truck, which has a mass , will

(a) Also negotiate the curve without slipping.

(b) Tend to slide down (i.e.. toward the inside of the curve) .

(c) Tend to slide up (i.e.. toward the outside of the curve) .

(d) None of these

Solution 1: (a)

Explanation:

For banked curved road we know

So, speed does not depend on mass.

Since small car was able to cross the road, the truck will also be able to cross the road

Question 2:

A car moves with a constant speed on the hilly road.

Pressure exerted by the car tyres on the road when the car crosses through dip between two hills

Pressure exerted by the car tyres on the road when the car crosses through top of the hills

Pressure exerted by the car tyres on the road when the car crosses through a level stretch near the bottom of the hill

(A)

(B)

(C)

(D) None of these.

Solution-2:

(a)

Explanation

At the dip between the two hills, the normal force needs to support both the centripetal force and weight of the car. So, it is largest

At the top of the hill, the weight will provide the support to both the normal force and centripetal force. So, it is least

On level normal, the normal force will only support the weight

## True or False Statement

Question 3:

Acceleration and velocity vector are perpendicular to each other at every point in uniform circular motion

Solution 3:

(True)

Explanation:

Acceleration is always directed towards the center and velocity is along the tangent

Question 4:

When a body moves in uniform circular motion, the kinetic energy of the body remains unchanged through-out the motion

Solution 4:

(True)

Explanation:

So, since speed is constant, KE remains unchanged

Question 5:

A ball is rotated in a horizontal circle with the help of string. If we cut the string in between, the ball will move along the tangent of the horizontal circle at that time

Solution 5:

(True)

Explanation:

When the string is cut, centripetal force disappears, and the object move along the straight-line path of the velocity

Question 6:

The outer rail is slightly higher than inside rail at the turning point to provide the centripetal force to the train at the curve

Solution 6:

(True)

Explanation:

The outer rail is slightly higher than inside rail to provide the centripetal force through Normal reaction

Question 7:

In the wall of death, the motorcycle cycle does not fall as the frictional force between wall and motorcycle acts upwards and balance the weight of the motorcycle

Solution 7:

(True)

Explanation:

In the wall of death, the normal force provides the centripetal force and frictional force support the weight of the body

Ram, Shyam and Manoj are riding a merry go round which is turning with constant angular velocity. They are at distance and respectively from the center of the merry go round. The distances are in this following order

All the person is having same mass approximately

Question 8:

Which person will experience highest acceleration?

a) Ram

b) Shyam

c) Manoj

d) Insufficient information

Question 9:

Which person will have lowest velocity?

a) Ram

b) Shyam

c) Manoj

d) Insufficient information

Question 10:

Which person must hold on the merry round most tightly?

a) Ram

b) Shyam

c) Manoj

d) Insufficient information

Solution 8 - 10

Explanation:

Each person will move in uniform circular motion and the centripetal force will be provide by their grip on merry go round. Now for each person, velocity, acceleration, and force can be given by

As Ram is at lowest distance, it will experience the lowest velocity

As Manoj is highest distance, it will experience highest velocity and highest acceleration

As mass are same and Manoj is at highest distance, he must hold on most tightly

8) c

9) a

10) c

## Multiple Choice Questions

Question 11:

What force is responsible for holding a car in an unbanked curve?

a) The horizontal component of the normal force

b) The vertical component of the normal force.

c) Frictional force

d) The car՚s weight

Solution 11:

(c)

Explanation:

In unbanked curve, the frictional force between the tires and road provides the necessary centripetal force

Question 12:

When a ball at rest hangs by a single vertical string, tension in the string is . If the ball is made to move in a horizontal circle so that the string describes a cone, string tension.

a) Is .

b) Is greater than , always.

c) . Is less than , always.

d) May be greater or less than Mg depending on the speed of the ball

Solution 12:

(b)

Question 13:

An object of mass is tied to a string of length L and whirled with speed v in circular path. Which of the following statement is correct?

a) The tension T and weight of the object will be only forces acting on the object

b) The tension T, Weight of the object and centripetal force mv2/R inwards will be acting on the object

c) The tension T, Weight of the object and centripetal force mv2/R outwards will be acting on the object

d) Not sufficient information

Solution 13:

(a)

Explanation:

Centripetal force is not any new kind of force. It is just a force. We require centripetal force for circular motion, but it comes from force exerting on the object only. So only tension and weight are the force acting on the object.

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