A car is being driven at a speed of 20 ms^-1 when brakes are applied to bring it to rest in 5 s. The decelaration produced in this case will be

(a)

+4 ms^-2

(b)

‒4 ms^-2

(c)

‒0.25 ms^-2

(d)

+0.25 ms^-2

Which one of the following is most likely not a case of uniform circular motion?

(a)

Motion of the Earth around the Sun

(b)

Motion of a toy train on a circular track

(c)

Motion of a racing car on a circular track.

(d)

Motion of hours' hand on the dial of the clock

The centrifugal force is

(a)

Real force

(b)

The force of reaction of centripetal force

(c)

Virtual force

(d)

Directed towards the centre of the circular path.

When a body starts from rest, the acceleration of the body after 2 second in _____________ of its displacement.

(a)

Half

(b)

Twice

(c)

Four times

(d)

One fourth

Force involved in uniform circular motion is given by _____________.

(a)

f = mv²/r

(b)

f = mvr

(c)

f = mr²/v

(d)

f = v²/r