A projectile is thrown with velocity $U=20\ m/s ± 5\%$ at an angle $60^o.$ If the projectile falls back on the ground at the same level then ......... $m$ of following can not be a possible answer for range.
$39.0$
$37.5$
$34.6$
$32.0$
A fighter plane flying horizontally at an altitude of $1.5\; km$ with speed $720\; km / h$ passes directly overhead an anti-atrcraft gun. At what angle from the vertical should the gun be fired for the shell with muzzle speed $600\; m s ^{-1}$ to hit the plane? At what minimum altitude should the pilot fly the plane to avoid being hit ? (Take $g=10 \;m s ^{-2}$ ).
The maximum height reached by a projectile is $64 \mathrm{~m}$. If the initial velocity is halved, the new maximum height of the projectile is_________.$\mathrm{m}$.
A body is projected from the ground at an angle of $45^{\circ}$ with the horizontal. Its velocity after $2s$ is $20 \,ms ^{-1}$. The maximum height reached by the body during its motion is $m$. (use $g =10\, ms ^{-2}$ )
A cricket fielder can throw the cricket ball with a speed $v_{0} .$ If he throws the ball while running with speed $u$ at an angle $\theta$ to the horizontal, find
$(a)$ the effective angle to the horizontal at which the ball is projected in air as seen by a spectator
$(b)$ what will be time of flight?
$(c)$ what is the distance (horizontal range) from the point of projection at which the ball will land ?
$(d)$ find $\theta$ at which he should throw the ball that would maximise the horizontal range as found in $(iii)$.
$(e)$ how does $\theta $ for maximum range change if $u > u_0$. $u =u_0$ $u < v_0$ ?
$(f)$ how does $\theta $ in $(v)$ compare with that for $u=0$ $($ i.e., $45^{o})$ ?
A cart is moving horizontally along a straight line with a constant speed of $30\,m / s$. A projectile is to be fired from the moving cart in such a way that it will retum to the cart (at the same point on cart) after the cart has moved $80\,m$. At what velocity (relative to the cart) must be projectile be fired? (Take $=10\,m / s ^2$ )