Exam-style question
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A ball is dropped from a height of 20 m. Calculate the gravitational potential energy at the top. Use g = 9.81 N/kg.
- A.196.2 J
- B.98.1 J
- C.20 J
- D.0 J
Model answer
What a good answer should say
- 196.2 J
Explanation
Why this works
The gravitational potential energy (Ep) can be calculated using the formula Ep = m x g x h. Assuming the mass (m) of the ball is 1 kg, we substitute: Ep = 1 kg x 9.81 N/kg x 20 m = 196.2 J.
Thus, the gravitational potential energy at the top is 196.2 J.
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