A body of mass 4.2kg moving with velocity 10ms−¹ due east, hits a stationary body of mass 2.8kg. If they stick together after collision and move with velocity V due east, calculate the value of V

A. 3ms−¹
B. 6ms−¹
C. 7ms−¹
D. 15ms−¹
E. 17ms−¹

Correct Answer:

Option B – 6ms−¹

Explanation

M1U = (M1 + M2)V = 4.2 x 10 = (4.2 = 2.8)V
∴ V = 4.2 x 10/7.0
= 6m/s