Question

Two paper screens $A$ and $B$ are separated by a distance of $100$ m. $A$ bullet pierces $A$ and then $B$. The hole in $B$ is $10$ cm below the hole in $A$. If the bullet is travelling horizontally at the time of hitting the screen $A$, calculate the velocity of the bullet when it hits the screen $A$. Neglect the resistance of paper and air.

Answer 1

Equation of motion in $x$-direction, $100=v\times t$

$\Rightarrow t=\frac{100}{v}$ ............(i)

In $y-$direction

$0.1=1/2\times 10\times r^2$

$0.1=1/2\times 10\times (100/v{)}^2$...........(ii)

From Eqs (i) and (ii), we get

$u=700m{s}^{-1}$