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Question : 85 of 100
Marks:
+1,
-0
Solution:
- Work:
- Work done on an object is defined as the magnitude of the force multiplied by the distance moved by the object in the direction of the applied force.
- The unit of work is the joule (1 Joule = 1 Newton-meter).
- Work done on an object by a force would be zero if the displacement of the object is zero.
- It is the dot product of force and displacement.
- It is a Scalar quantity.
- W = F.s cosθ.
- Distance:
- The length of the actual path covered by a moving object in a given time.
- It is a scalar quantity.
- It is always positive.
- The unit of distance is a meter (m).
- Displacement:
- It is the shortest distance covered by a body in a definite direction.
- It is a vector quantity.
- It can be positive, Negative, or Zero.
- The unit of displacement is a meter(m).
- In this question, we can see that work done would be zero in all the above options except option 3.
- In this case, when Pinki is carrying a book on his head, the gravitational force acts on his head and presses his head to make some displacement.
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