Question

A smooth square platform ABCD is moving towards right with a uniform speed v. At what angle q must a particle be projected from A with speed u so that it strikes the point B –

• A. sin^–1$\left( \frac{u}{v} \right)$
• B. cos^–1$\left( \frac{v}{u} \right)$
• C. cos^–1$\left( \frac{u}{v} \right)$
• D. sin^–1$\left( \frac{v}{u} \right)$

Answer 1

Answer: (B)

cos^–1$\left( \frac{v}{u} \right)$

Answer 2

Particle will strike the point B if velocity of particle with respect to platform is along AB or component of its relative velocity along AD is zero i.e.,

u cos q = v

or q = cos^–1$\left( \frac{v}{u} \right)$