Question

A projectile is moving at 60 m/s at its highest point, where it breaks into two equal parts due to an internal explosion. One part moves vertically up at 50 m/s with respect to the ground. The other part will move at

• A. 110 m/s
• B. 120 m/s
• C. 130 m/s
• D. 10$\sqrt{61}$ m/s

Answer 1

The correct option is C 130 m/s

Let the other part moves with velocity $v$ making an angle $\theta$ with the x axis.

Applying conservation of momentum :

$x$ direction : $\left(2m\right)60=mv$ $cos\theta$

$⟹120=vcos\theta$ ..............(1)

$y$ direction : $m\times 50=mv$ $sin\theta$

$⟹50=vsin\theta$ ..............(2)

Squaring and adding (1) and (2), ${120}^2+{50}^2=v^2$

$\therefore$ $v^2=16900$

$⟹v=130$ $m{s}^{-1}$