Define 1 Joule (J) of work.
One joule of work is done when a force of one newton displaces a body through a distance of 1 metre in its own direction.
Write an expression for the work done when a force is acting on an object in the direction of its displacement.
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?
When do we say that work is done?
Look at the activities listed below. Reason out whether or not work is done in the light of your understanding of the term ‘work’:
(i) Suma is swimming in a pond.
(ii) A donkey is carrying a load on its back.
(iii) A wind mill is lifting water from a well.
(iv) A green plant is carrying out photosynthesis.
(v) An engine is pulling a train.
(vi) Food grains are getting dried in the sun.
(vii) A sailboat is moving due to wind energy.
