Exam-style question
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A 2 kg object is lifted to a height of 5 m. Calculate the work done against gravity.
- A.10 J
- B.20 J
- C.100 J
- D.50 J
Model answer
What a good answer should say
- 100 J
Explanation
Why this works
The work done (W) against gravity can be calculated using the formula W = F x s, where F is the weight (mg). Here, F = 2 kg x 9.81 N/kg = 19.62 N.
Therefore, W = 19.62 N x 5 m = 98.1 J, which rounds to 100 J. Thus, the work done against gravity is 100 J.
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