A force of 20 N acts on an object for 4 seconds. What is the impulse of the force?
Correct: C
The impulse of the force can be calculated using the formula J = F * t, where J is the impulse, F is the force, and t is the time. Given F = 20 N and t = 4 seconds, we can calculate J = 20 * 4 = 80 Ns.