Chapter 10 Work and Energy Questions-02
Questions
1. When do we say that work is done?
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Answer
Work is done whenever the given conditions are satisfied:
(i) A force acts on the body.
(ii) There is a displacement of the body caused by the applied force along the direction of the applied force.
2. Write an expression for the work done when a force is acting on an object in the direction of its displacement.
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Answer
When a force $F$ displaces a body through a distance $S$ in the direction of the applied force, then the work done W on the body is given by the expression:
Work done $=$ Force $\times$ Displacement
$W=F \times s$
3. Define $1 J$ of work.
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Answer
$1 J$ is the amount of work done by a force of $1 N$ on an object that displaces it through a distance of $1 m$ in the direction of the applied force.
4. 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?
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Answer
Work done by the bullocks is given by the expression:
Work done $=$ Force $\times$ Displacement
$W=F \times d$
Where,
Applied force, $F=140 N$
Displacement, $d=15 m$
