Work and Energy · Class 9 · CBSE Science
A girl is carrying a school bag of mass 3 kg on her back and walks a horizontal distance of 100 m. How much work is done by the girl against the forc…
Practice question from Work and Energy (Class 9 · CBSE Science), with the correct answer and a step-by-step solution.
medium · MCQ · Q-63BC8A
A girl is carrying a school bag of mass 3 kg on her back and walks a horizontal distance of 100 m. How much work is done by the girl against the force of gravity? (Take )
- A.2940 J
- B.300 J
- C.0 JCorrect answer
- D.294 J
Solution
Work done is . The force of gravity acts vertically downwards while the displacement of the bag is horizontal. The angle between the gravitational force and displacement is . Since , the work done against gravity is zero.
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