Question

A constant horizontal force of 5.0 N is applied to a 1.2 kg cart. The cart is initially at rest. How fast will it be moving after a time of 3.0 seconds

Answer 1

$$F\Delta t=m\Delta v,$$ $$F\Delta t=m(v_f-v_i)=mv_f,$$ $$v_f=\dfrac{F\Delta t}{m}=\dfrac{5.0\ N\cdot3.0\ s}{1.2\ kg}=12.5\ \dfrac{m}{s}.$$