A ball of mass 4 kg is initially traveling at 2 m/s and has a 5 N force applied to it for 3 s. What is the final velocity of the ball?

Answer 1

Solution:

Given : Initial Velocity Vi = 2 m/s, Force F = 5 N, Mass m = 4 kg, and time t = 3 s

Need: Final velocity Vf =?

from Kinematics Vf - Vi = a t , where a is the ball acceleration

From Newton 2nd law, F = ma, and a = F/m = 5 N / 4 Kg = 5 kg-m/s² / 4 kg = 1.25 m/s²

Then Vf - 2m/s = ( 1.25 m/s²) ( 3 s) = 3.75 m/s, and Vf = 3.75 m/s + 2 m/s = 5.75 m/s