What is the acceleration of the block?

Question

A 5 kg block experiences two external forces acting on it simultaneously. Force A has a magnitude of 5 N and points in the positive direction. Force B has a magnitude of 25 N and points in the negative direction. What is the acceleration of the block? 

Answer 1

Question: What is the acceleration of the block?

A 5 kg block experiences two external forces acting on it simultaneously. Force A has a magnitude of 5 N and points in the positive direction. Force B has a magnitude of 25 N and points in the negative direction. What is the acceleration of the block? 

This is a net Force question (Newton's second law) where the net force is the sum of all forces acting in a system.

F_net = ma = ∑F_n = +5 + (-25) = -20 where the signs, as the convention would have it, indicate positive to the right and negative to the left. Using Newton's second law of motion: F_net = ma: -20 = 5*a; a = -20/5 = -4 m/sec². The block experiences an acceleration of 4 m/sec² to the left.