Question

A body of mass 2kg was moving with a velocity of 10 ms-1 when a force F is applied on it. Find the magnitude and direction of F if (1) the body stops after 10s. (2) it acquires a velocity of 20 ms-1 in travelling a distance of 15m after application of the force.

Answer 1

here
m=2kg, u=10ms-1, v=0, t=10s

v=u+at

0=10+a.10. ==>a=-1
F=ma =2×-1=-2N