ECAT Physics MCQs

A surface exerts a normal force on an object in contact with it.
Its magnitude is not always equal to weight.

Use v²=u²+2as.
100-16 = 42a, so a=2 m/s².

Friction acts tangentially at a contact surface.
It may be static or kinetic.

Starting from rest, v=gt.
V=10×2 = 20 m/s.

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

Use s=½gt².
S=½×10×9 = 45 m.

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

At maximum height, final vertical velocity is zero.
0=20-10t gives t=2 s.

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

Use v²=u²-2gh with v=0.
0=400-20h, so h=20 m.

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

Newton's second law gives F=ma.
F=5×4 = 20 N.