A projectile is fired at a target in such a way that the projectile leaves the gun at the same time the target is dropped from rest. Show that if the gun is initially aimed at the stationary target, the projectile hits the falling target as shown in the picture:
http://imageshack.us/a/img818/6193/0rpy.jpg

What I don't get is why the condition can only occur under the following condition:
V_ip*sin(theta) = sqroot(gd/2) where d is the initial elevation of the target. I would say x_P = x_T but then how do I get to the inequation above?

Question

A projectile is fired at a target in such a way that the projectile leaves the gun at the same time the target is dropped from rest. Show that if the gun is initially aimed at the stationary target, the projectile hits the falling target as shown in the picture:
http://imageshack.us/a/img818/6193/0rpy.jpg

What I don't get is why the condition can only occur under the following condition:
V_ip*sin(theta) >= sqroot(gd/2) where d is the initial elevation of the target. I would say x_P >= x_T but then how do I get to the inequation above?

anonymous · Answer

*why the collision can only occur

anonymous · Answer

attachment

anonymous · Answer

$$v _{iP}\times \sin \theta \ge \frac{\sqrt{ g\times d }}{ 2 }$$