JEE Main20209 Jan 2020Evening ShiftPhysicsCenter of Mass, Momentum and CollisionActual
A particle of mass m is projected with a speed u from the ground at an angle θ = π 3 w.r.t. horizontal (x-axis). When it has reached its maximum height, it collides completely inelastically with another particle of the same mass and velocity u i ^ . The horizontal distance covered by the combined mass before reaching the ground is:
Options
- A3 3 8 u 2 g
- B3 2 4 u 2 g
- C5 8 u 2 g
- D2 2 u 2 g
Correct answer
A. 3 3 8 u 2 g
Step-by-step solution
p i = p f m u + m u c o s θ = 2 m v ⇒ v = u 1 + cos ⁡ 60 0 2 = 3 4 u So horizontal range after collision = v t = v 2 H m a x g = 3 4 u 2 u 2 sin 2 ⁡ 60 0 2 g 2 = 3 4 u 2 3 4 g = 3 3 u 2 8 g