How long will it take a force of 10 N to stop a mass of 2.5 kg which is moving at 20 m/s?
Force applied (F) = -10 N (since the force is acting in the opposite direction of motion or opposing the motion)
Mass of body (m) = 2.5kg
Initial velocity of body (u) = 20m/s
Final velocity of body (v) = 0m/s
According to Newton's second law of motion
F = ma
-10 = 2.5×a
-10/2.5 = v-u/t (since a = v-u/t)
-4t = 0 - 20
t = -20/-4
t = 5 sec