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

A projectile is projected at $30^{\circ}$ from horizontal with initial velocity $40\,ms ^{-1}$. The velocity of the projectile at $t =2\,s$ from the start will be $........$ (Given $g =10\,m / s ^2$ )

What is the path followed by a moving body, on which a constant force acts in a direction other than initial velocity (i.e. excluding parallel and antiparallel direction)?

A ball of mass $160\, g$ is thrown up at an angle of $60^o$ to the horizontal at a speed of $10\, m\,s^{-1}$ . The angular momentum of the ball at the highest point of the trajectcry with respect to the point from which the ball is thrown is nearly ........ $kg\, m^2/s$  $(g\, = 10\, m\,s^{-2})$

A projectile $A$ is thrown at an angle $30^{\circ}$ to the horizontal from point $P$. At the same time another projectile $B$ is thrown with velocity $v_2$ upwards from the point $Q$ vertically below the highest point $A$ would reach. For $B$ to collide with $A$, the ratio $\frac{v_2}{v_1}$ should be

A stone is projected from ground at $t = 0$. At the time of projection horizontal and vertical component of velocity are $10\, m/s$ and $20\, m/s$ respectively. Then time at which tangential and normal acceleration magnitude will be equal $(g = 10\, m/s^2)$ [neglect air friction]    ......... $\sec$