Q. A particle $A$ is projected from the ground with an initial velocity of $10\, m \,s ^{-1}$ at an angle of $60^{\circ}$ with horizontal. From what height should another particle $B$ be projected horizontally with velocity $5 \,m \,s ^{-1}$ so that both the particles collide in ground at point $C$ if both are projected simultaneously. (Take $\left.g=10 \,m \,s ^{-2}\right)$
Motion in a Plane
Solution: