A seventh-grader, 162 cm tall, lifted a physics textbook weighing 315 g to a height of 1.94 m above the floor.

A seventh-grader, 162 cm tall, lifted a physics textbook weighing 315 g to a height of 1.94 m above the floor. What is the potential energy of the book in relation to gender and; relative to the top of the girl’s head.

Given: hд (the height of the seventh grader) = 162 cm = 1.62 m; m (the mass of a physics textbook) = 315 g = 0.315 kg; h (textbook height above the floor) = 1.94 m.

Constants: g (acceleration due to gravity) ≈ 10 m / s2.

1) Potential energy of the textbook above the floor: En1 = m * g * h = 0.315 * 10 * 1.94 = 6.111 J.

2) Potential energy relative to the crown: En2 = m * g * (h – hd) = 0.315 * 10 * (1.94 – 1.62) = 1.008 J.

Answer: The potential energy of the textbook relative to the floor is 6.111 J, relative to the crown – 1.008 J.