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Practice each question, then open the answer or worked solution.
When do we say that work is done?
Work is completed whenever the given conditions are satisfied:
(i) A force acts on the body.
(ii) There’s a displacement of the body by applying force in or opposite to the direction of the force.
Write an expression for the work done when a force is acting on an object in the direction of its displacement.
When a force F displaces a body through a distance S within the direction of the applied force, then the work done W on the body is given by the expression:
W = F × S
Define 1 J of work.
1 J is the amount of work done on an object when a force of 1 N displaces it by 1 m along the line of action of the force.
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?
Work done by the bullocks is given by the expression:
W= F × d
Where,
Applied force, F = 140 N
Displacement, d = 15 m
W = 140 x 15 = 2100 J
Therefore, 2100 J of work is done in ploughing the length of the field.