The power of a motor pump is $2 \, kW$. How much water per minute can the pump raise to a height of $10 \, m$ (in $kg$)? (Given $g = 10 \, m \, s^{-2}$)

Which would have a greater effect on the kinetic energy of an object: doubling the mass,or doubling the velocity?

How is the power related to the speed at which a body can be lifted? How many kilograms will a man working at the power of $100\, W$ be able to lift at a constant speed of $1\, m\, s^{-1}$ vertically (in $, kg$)? $(g = 10\, m\, s^{-2})$

Justify,giving proper reasoning,whether the work done in the following case is positive or negative: Work done by friction on a body sliding down an inclined plane.

$A$ person is climbing a palm tree:
$(i)$ What is the work done against the force of gravity?
$(ii)$ What is the work done by the force applied by the person if the person climbs $10 \, m$ and the mass of the person is $45 \, kg$?

$(i)$ An object thrown at a certain angle to the ground moves in a curved path and falls back to the ground. The initial and the final points of the path of the object lie on the same horizontal line. What is the total work done against the force of gravity and by the force of gravity on the object? Explain with proper mathematical expression.
$(ii)$ $A$ certain force acting on a $20 \, kg$ mass changes its velocity from $5 \, m s^{-1}$ to $2 \, m s^{-1}$. Calculate the work done by the force.