Identify the kind of energy possessed by a running athlete.

Can any object have momentum even if its mechanical energy is zero? Explain.

$A$ horse of mass $210\, kg$ and a dog of mass $25\, kg$ are running at the same speed. Which of the two possesses more kinetic energy? How?

Define kinetic energy and potential energy. Write an expression for $KE$ of a body of mass $m$ moving with speed $v$. Find the kinetic energy of a stone of $10 \, kg$ moving with a velocity of $10 \, m s^{-1}$.

$(a)$ Give two conditions for work to be done.
$(b)$ What is the work done by frictional force on an object when dragged along a rough surface?
$(c)$ Relate power and work.
$(d)$ $A$ machine does $1960 \, J$ of work in $4 \, \text{minutes}$. What is the power?

When a force retards the motion of a body,the work done is: