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 $, kg$)? $(g = 10\, m\, s^{-2})$

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

Find the velocity of a body of mass $100 \, g$ having a kinetic energy of $20 \, J$. (in $, m s^{-1}$)

$(a)$ Derive an expression for the kinetic energy of a body having mass $m$ and moving with a velocity $v$.
$(b)$ When the velocity of a body is increased $5$ times,what is the change in its kinetic energy?
$(c)$ Two masses $m$ and $2m$ are dropped from heights $h$ and $2h$. On reaching the ground,which will have greater kinetic energy and why?

At what speed will a body of mass $1\, kg$ have a kinetic energy of $1\, J$ (in $, m/s$)?

$A$ girl of mass $40\, kg$ climbs a rope $6\, m$ long at a constant speed in $15$ seconds. What power does she expend during the climb (in $W$)?