Work and Energy...

An electric heater of power $$3 \ kW$$ is used for $$10 \ h$$. How much energy does it consume? Express your answer in joule.

A body is moved in a direction opposite to the direction of force acting on it. Work is done is:

Write an expression for the work done when a force is acting on an object in the direction of its displacement.

Name the type of energy (kinetic energy $$K$$ or potential energy $$U$$) possessed in the following case.

A pair of bullocks exerts a force of 140 N on a plough. The field being ploughed is 15 m long. How much work is done in ploughing the length of the field ?

The energy consumed by $$100 \ W$$ electric bulb in $$5 \ hours$$ is:

A man is waiting for a bus. What is the work done when he is carrying a box and waits for 5 minutes for the bus?

 A force of 7 N acts on an object. The displacement is 8 m, in the direction of the force. Consider force acting on the object through the displacement. What is the work done in this case ? 

An engine pulls a train 1 km over a level track. Calculate the work done by the train against friction if frictional force is $$5 \times 10^5 N$$.