Per NCERT Example 7.2, a goalkeeper's hand moves back by 15 cm while applying a force of 200 N to stop a ball. What work does the goalkeeper do on the ball?
AZero
B+30 J
C−30 J (negative work since force opposes ball's motion)
D+0.3 J
Answer & Solution
Correct answer: C. −30 J (negative work since force opposes ball's motion)
Per NCERT Example 7.2, W = 200 N × (−0.15 m) = −30 J. Force and displacement are opposite, so work is negative.
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