Question

A book was dropped from a height of 4.2 meters has 109 joules of potential energy. What is the mass of the book?



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Answer 1

Answer:

$P.E=mgh \\ 109 = m(9.81)(4.2) \\ m = \frac{109}{9.81 \times 4.2} \\ \boxed{m = 2.6455 \: kg}$