Question

A book starts on a shelf 1 m off of the ground. You then move the book to a higher shelf that is 3 m off of the ground. If the system gained 20 J of gravitational potential energy, what is the mass of the book?

Answer 1

Using g = 9.8: 1.02 kg, Using g = 10: 1 kg

Step-by-step explanation:

E = mgh

20 = m(9.8)(3 - 1)

20 = 9.8m(2)

20 = 19.6m

m = 1.02 kg

I'm now assuming you may be using a g constant of 10, thus the close integer result, in which case the mass would be exactly 1 kilogram.