ECAT Physics MCQs

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.

Acceleration is net force divided by mass.
A=30/6 = 5 m/s².

For conservative forces, work around a closed path is zero.
Gravity and ideal spring force are examples.

Weight is W=mg.
W=7×10 = 70 N.

Linear momentum is a vector quantity p=mv.
Its direction is the direction of velocity.

Vertical equilibrium requires normal force to balance weight.
N=mg=10×10 = 100 N.

Impulse equals force integrated over time.
For constant force, J=FΔt=Δp.

Opposing forces subtract.
Net force = 50-20 = 30 N.

Internal forces cancel in pairs within a system.
With no net external impulse, total momentum remains constant.