A shell is fired from a fixed artillery gun with an initial speed $u$ such that it hits the target on the ground at a distance $R$ from it. If $t_1$ and $t_2$ are the values of the time taken by it to hit the target in two possible ways, the product $t_1t_2$ is
$2R/g$
$R/4g$
$R/g$
$R/2g$
A projectile is thrown into space so as to have a maximum possible horizontal range of $400$ metres. Taking the point of projection as the origin, the co-ordinates of the point where the velocity of the projectile is minimum are
A projectile can have the same range $R$ for two angles of projection. If $t_1$ and $t_2$ be the times of flights in the two cases, then the product of the two time of flights is proportional to
Which of the following is the graph between the height $(h)$ of a projectile and time $(t)$, when it is projected from the ground
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 particle is projected from the ground at an angle of $\theta $ with the horizontal with an initial speed of $u$. Time after which velocity vector of the projectile is perpendicular to the initial velocity is