A body is travelling with $$10 \mathrm{~ms}^{-1}$$ on a rough horizontal surface. It's velocity after 2 s is $$4 \mathrm{~ms}^{-1}$$. The coefficient of kinetic friction between the block and the plane is (acceleration due to gravity $$=10 \mathrm{~ms}^{-2}$$)
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
Ball $$A$$ of mass 1 kg moving along a straight line with a velocity of $$4 \mathrm{~ms}^{-1}$$ hits another ball $$B$$ of mass 3 kg which is at rest. After collision, they stick together and move with the same velocity along the same straight line. If the time of impact of the collision is 0.1 s then the force exerted on $$B$$ is