Question

A cart of mass 20 kg, initially at rest, is pushed with a net force of 40 N on a flat surface. If the cart is pushed 5 m, what is the final kinetic energy (KE)? What is the final velocity? (Assume no heat losses.)

Answer 1

using the theorem of kinetic energy
1/2mVf² - 1/2mVi²= WF + Wp, Wp=0
WF = F. AB, AB=5m and F= 40N, m=20kg
so the final kinetic is KEf= 1/2mVf² = WF =F. AB= 40*5=200J

the final velocity is 1/2mVf² =200, implies Vf= sqrt(20)=2sqrt(5)m/s