At the top of the trajectory of a projectile, the acceleration is
Maximum
Minimum
Zero
$g$
A gun can fire shells with maximum speed $v_0$ and the maximum horizontal range that can be achieved is $R_{max} = \frac {v_0^2}{g}$. If a target farther away by distance $\Delta x$ (beyond $R$) has to be hit with the same gun, show that it could be achieved by raising the gun to a height at least $h = \Delta x\,\left[ {1 + \frac{{\Delta x}}{R}} \right]$.
A wheel of radius $R$ is trapped in a mud pit and spinning. As the wheel is spinning, it splashes mud blobs with initial speed $u$ from various points on its circumference. The maximum height from the centre of the wheel, to which a mud blob can reach is
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
The initial velocity of a particle of mass $2\,kg$ is $(4 \hat{ i }+4 \hat{ j })\,m / s$. A constant force of $-20 \hat{ j }\,N$ is applied on the particle. Initially, the particle was at $(0,0)$. Find the $x$-coordinate of the point where its $y$-coordinate is again zero.$..........\,m$