Question

Two particles start moving simultaneously from the same place in same direction, one with constant velocity 50 m/s and the other with uniform acceleration 10 m/s^2. After 5 sec, distance between them will be?

Answer 1

We can do it by relative motion concepts. From frame of 1st particle, u21 = -50 and a21 = 10.

s21 = 125 = u21 t + 1/2 a21 t2 = -50t + 1/2 10 t2  

=> 25 = -10t + t2

Solving: t = 5 + 5 sqrt(2) = 5 (1 + sqrt(2)) seconds