A door $$1.2 \mathrm{~m}$$ wide requires a force of $$1 \mathrm{~N}$$ to be applied perpendicular at the free end to open or close it. The perpendicular force required at a point $$0.2 \mathrm{~m}$$ distant from the hinges for opening or closing the door is

A spring balance is attached to the ceiling of a lift. A man hangs his bag on the spring and the spring balance reads $$49 \mathrm{~N}$$, when the lift is stationary. If the lift moves downward with an acceleration of $$5 \mathrm{~m} / \mathrm{s}^2$$, the reading of the spring balance will be $$(\mathrm{g}=9.8 \mathrm{~m} / \mathrm{s}^2)$$

The weight of a man in a lift moving upwards with an acceleration 'a' is 620 N. When the lift moves downwards with the same acceleration, his weight is found to be 340 N. The real weight of the man is

A block of mass $$m$$ is moving on rough horizontal surface with momentum $$p$$. The coefficient of friction between the block and surface is $$\mu$$. The distance covered by block before it stops is [$$g=$$ acceleration due to gravity]