Pakistan MCQs

Centripetal acceleration changes the direction of velocity.
It always points radially inward.

Centripetal force is not a separate force type.
It may be supplied by tension, friction, gravity, or another force.

A particle in translational equilibrium has no acceleration.
It may be at rest or moving at constant velocity.

In ideal free fall, air resistance is neglected.
All objects then have the same gravitational acceleration locally.

Average speed equals distance divided by time.
120/10 = 12 m/s.

Displacement is 14-2 = 12 m.
Average velocity is 12/4 = 3 m/s.

Average speed uses total distance.
400/80 = 5 m/s.

The runner returns to the starting point, so displacement is zero.
Average velocity is therefore zero.

Use v=u+at with u=0.
V=0+3×4 = 12 m/s.

Use v=u+at.
V=5+2×6 = 17 m/s.

At terminal velocity, net force is zero.
The object then moves with constant velocity.

Average velocity is a vector based on net displacement.
A round trip can have zero average velocity.