Question

Study the statement given below and find which is true?

I. When a bus suddenly stopped the passengers tend to fall forward.

II. When stone is rotated in a circle of smaller radius, greater force is required.

III. At optimum speed frictional force is not needed at all to provide the necessary centripetal force in case of banked road. 

(a) I only 

(b) I and II

(c) I, II and III

(d) All are false

Answer 1

Answer- (b)

Explaination:

1) As bus is moving forward passengers in the bus have inertia to move in forward direction. They are also in motion in forward direction but when breaks are applied their body inertia tries to resist change in their initial forward motion so they continue in forward direction and fall.

2) Centripetal Force is the required force to be in circular motion. F=mv²/r... Force is inversely proportional to radius so when radius is less more force is required.

3) In banking Frictional force functions as required Centripetal Force. so it is required. Hence the 3rd statement is wrong.

Comments

Answer 2

Correct option is (b) I and II

Except III all statements are correct. Friction is needed for turning on banked track also