Question

a smooth square platform abcd is moving towards right with a uniform speed v. at what angle must a particle be projected from a with speed u so that it strikes the point b

Answer 1

HorizontalDistance moved by platform=v×t

Horizon distance by projectile= ucos(∆)×t

Where ∆ is the angle

To meet at point D horizontal distance should be same ucos(∆)×t=v×t

∆=cos^-1(v/u)