$A$ boy weighing $50 \ kg$ finished a long jump at a distance of $8 \ m$. Considering that he moved along a parabolic path and his angle of jump is $45^{\circ}$,his initial $K.E.$ is (in $J$)

$A$ particle is projected with velocity $u$ at an angle $\alpha$ with the horizontal,and another particle is projected with the same velocity $u$ at an angle $\alpha$ with the vertical. What is the ratio of their times of flight?

$A$ bullet is dropped from a certain height,and at the same instant,another bullet is fired horizontally from the same height. Which bullet will hit the ground first?

$A$ ball is thrown from a point on the ground at some angle of projection. At the same time,a bird starts from a point directly above this point of projection at a height $h$ and moves horizontally with speed $u$. Given that in its flight,the ball just touches the bird at one point. Find the distance on the ground where the ball strikes.

$A$ body is projected with a velocity $u$ at an angle $\theta$ with the horizontal. If the time of ascent of the body is $1 \ s$,then the maximum height it can reach is (Take $g = 10 \ m/s^2$) (in $m$)

$A$ projectile covers double the range compared to its maximum height attained. The angle of projection is