A small disc of mass $$m$$ slides down with initial velocity zero from the top $$(A)$$ of a smooth hill of height $$H$$ having a horizontal portion $$(BC)$$ as shown in the figure. If the height of the horizontal portion of the hill is $$h$$, then the maximum horizontal distance covered by the disc from the point $$D$$ is

A block of mass 50 kg is pulled with a constant speed of $$4 \mathrm{~ms}^{-1}$$ across a horizontal floor by an applied force of 500 N directed $$30^{\circ}$$ above the horizontal. The rate at which the force does work on the block in watt is

A ball of mass 300 g is dropped from a height 10 m above a sandy ground. On reaching the ground, it penetrates through a distance 1.5 m in sand and finally stops. The average resistance offered by the sand to oppose the motion is (acceleration due to gravity $$=10 \mathrm{~ms}^{-2}$$)