An electric heater is rated $1500 \, W$. How much energy does it use in $10$ hours?

The kinetic energy of an object of mass,$m$ moving with a velocity of $5 \,m \,s^{-1}$ is $25\, J$. What will be its kinetic energy when its velocity is doubled? What will be its kinetic energy when its velocity is increased three times?

Calculate the work required to be done to stop a car of $1500 \, kg$ moving at a velocity of $60 \, km/h$. (in $J$)

Write an expression for the kinetic energy of an object.

Look at the activities listed below. Reason out whether or not work is done in the light of your understanding of the term 'work'.
$1$. Suma is swimming in a pond.
$2$. $A$ donkey is carrying a load on its back.
$3$. $A$ windmill is lifting water from a well.
$4$. $A$ green plant is carrying out photosynthesis.
$5$. An engine is pulling a train.
$6$. Food grains are getting dried in the sun.
$7$. $A$ sailboat is moving due to wind energy.

Define $1\, J$ of work.