A 2-kg rests top of a table 80 cm from the floor. Find the potential energy of the book relative to (a) the floor, (b) the seat of a chair 40 cm from the floor, and (c) relative to ceiling 3m from the floor? Steps please, thank you ^_^

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Answer 1 · 2017-11-25T00:53:12

(a) Potential energy relative to floor

With respect to floor book is #"0.8 m"# high

Potential energy#= mgh = "2 kg × 9.8 m/s"^2 × "0.8 m" = "15.68 Joule"#

(b) Potential energy relative to seat of the chair

With respect to seat of the chair book is #"0.4 m"# high

Potential energy#= mgh = "2 kg × 9.8 m/s"^2 × "0.4 m" = "7.84 Joule"#

(c) Potential energy relative to ceiling

#"3 m - 0.8 m = 2.2 m"#

Book is #"2.2 m"# below ceiling

Potential energy#= mgh = "2 kg × 9.8 m/s"^2 × "-2.2 m" = "-43.12 Joule"#