Pakistan MCQs

Centripetal acceleration is v²/r.
A=100/20 = 5 m/s².

Acceleration is F/m = 4 m/s².
Change in velocity is at=4×3 = 12 m/s.

The net force is 80-20 = 60 N.
Acceleration is 60/15 = 4 m/s².

Constant velocity means zero acceleration and zero net force.
The normal force therefore equals the person's weight, 600 N.

Work transfers energy when a force acts through a displacement.
Only the component of force along displacement contributes.

Kinetic energy depends on mass and speed.
For translational motion, K=½mv².

Near Earth's surface, gravitational potential energy is mgh.
Only changes in potential energy are physically significant.

Power measures how quickly work is done.
Its SI unit is the watt.

The net work on an object changes its kinetic energy.
This relation is valid for the total work of all forces.

Conservative forces transfer energy between kinetic and potential forms.
Nonconservative work changes total mechanical energy.

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.