Question

If two people are applying 10 N and 20 N force respectively on an object on opposite directions, what is the net force? Is it 10 N or -10 N ?

Answer 1

Positive and negative value of force just denote the direction.Net force will be positive and negative based on the positive and negative direction we assumed.

If we assume direction in which 10N is positive x direction and force 20 N working in negative x direction than net force = 10-20 = -10N in negative x direction.

If we assume 20N is acting in positive x direction and 10N in negative x direction so net force = 20-10 = 10 N in positive x direction