A uniform rod pivoted at its upped end hangs vertically. It is displaced through an angle of 60∘ and then released. Find the magnitude of the force acting on a particle of mass dm at the tip of the rod when the rod makes an angle of 37∘ with the vertical.
A block placed on a horizontal surface is being pushed by a force F making an angle θ with the vertical. If the friction coefficient is μ, how much force is needed to get the block just started.