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In physics, when is work done on an object by a force?
AWhen it acts across the motion
BWhen it acts along the motion
CWhenever the object has mass
DWhenever the object is heavy
Answer & Solution
Correct answer: B. When it acts along the motion
1. Work is the process of transferring energy by means of a force.
2. That transfer needs the object to move while the force acts on it.
3. It also needs part of the force to lie along the line of that movement.
4. So work is done when the force acts in, or against, the direction of the motion.
_Source: Siyavula Physical Sciences Grade 12 (Everything Science, CC BY 4.0), Chapter 5: Work, energy and power_
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