A stuntman plans to run along a roof top and then horizontally off it to land on the roof of next building. The roof of the next building is $4.9$ metres below the first one and $6.2$ metres away from it. What should be his minimum roof top speed in ${\mathrm{ms}}^{-1}$, so that he can successfully make the jump?

A particle is projected horizontally with a speed of $\frac{20}{\sqrt{3}}{\mathrm{ms}}^{-1}$, from some height at $t=0$. At what time will its velocity make $60°$ angle with the initial velocity

A particle is projected horizontally with a speed of $\frac{20}{\sqrt{3}}{\mathrm{ms}}^{-1}$, from some height at $\mathrm{t}=0$.

what will be the displacement of the particle in $x$-direction when its velocity makes $60°$ angle with the initial velocity

A boy wants to jump from building $A$ to building $B$. Height of building $A$ is $25 \mathrm{m}$ and that of building $B$ is $5\mathrm{m}$. Distance between buildings is $4\mathrm{m}$. Assume that the boy jumps horizontally, then calculate minimum velocity with which he has to jump to land safely on building $\mathrm{B}$.