I think they just want you to rewrite it two other ways:
When a the irregularities of one surface come into contact with those of another surface ,occurs
1 answer:
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Answer:
Work done to pull the piano upwards is 401250 J
Explanation:
Work is done against the gravity to pull the piano upwards
So here we can say that work done is
here we know that
also we know that
H = 75 m
now we have