A hiker stands on the edge of a cliff $$490 \mathrm{~m}$$ above the ground and throws a stone horizontally with an initial speed of $$15 \mathrm{~ms}^{-1}$$. The speed with which it hits the ground is

Two paper screens $$A$$ and $$B$$ are separated by $$150 \mathrm{~m}$$. A bullet pierces $$A$$ and than $$B$$. The hole in $$B$$ is $$15 \mathrm{~cm}$$ below the hole in $$A$$. If the bullet is travelling horizontally at the time of hitting $$A$$, then the velocity of the bullet at $$A$$ is $$\left(\mathrm{g}=10 \mathrm{~ms}^{-2}\right)$$

A boy throws a cricket ball from the boundary to the wicket keeper. If the frictional force due to air $$(f_a )$$ cannot be ignored, the forces acting on the ball at the position X are represented by

A particle of mass m is projected with a velocity u making an angle $$\theta$$ with the horizontal. The magnitude of angular momentum of the projectile about the point of projection when the particle is at its maximum height is