Question

A net force of 40N south acts on an object with a mass of 20 kg. what is the object's acceleration?
A. a= 4 m/s2 north
B. a= 20 m/s2 north
C. a= 10 m/s2 south
D. a= 2 m/s2 south

Answer 1

Force is proportional to acceleration, so both the force and acceleration vectors should have the same direction of north.

Specifically, Newton's second law says that F = m a. Omitting direction, we can solve for a :

40 N = (20 kg) a   ==>   a = (40 N) / (20 kg) = 2 m/s²

so the answer is D.