A projectile fired at $30^{\circ}$ to the ground is observed to be at same height at time $3 s$ and $5 s$ after projection, during its flight. The speed of projection of the projectile is $.........\,ms ^{-1}$(Given $g=10\,m s ^{-2}$ )

 The $x-t$ graph of a particle moving along a straight line is shown in figure The $v-t$ graph of the particle is correctly shown by

Two projectiles $A$ and $B$ are thrown with the same speed such that $A$ makes angle $\theta$ with the horizontal and $B$ makes angle $\theta$ with the vertical, then

Figure shows four paths for a kicked football. Ignoring the effects of air on the flight, rank the paths according to initial horizontal velocity component, highest first

The angle of projection at which the horizontal range and maximum height of projectile are equal is

Four bodies $P, Q, R$ and $S$ are projected with equal velocities having angles of projection $15^o , 30^o , 45^o $  and $60^o $ with the horizontal respectively. The body having shortest range is