A pole vaulter clears the bar at a height of 5.4 m, and then falls to the safety mat. The change in the pole vaulter’s gravitational potential energy from the bar to the mat is –3.1 x 103 J. Calculate the pole vaulter’s mass

When an 81.0 kg adult uses a spiral staircase to climb to the second floor of his house, his gravitational potential energy increases by 2.00×10³ J. By how much does the potential energy of a 18.0 kg child increase when the child climbs a normal staircase to the second floor?

A box of unknown mass is sliding with an initial speed v₁ = 4.30 m/s across a horizontal frictionless warehouse floor when it encounters a rough section of flooring d = 2.80 m long. The coefficient of kinetic friction between the rough section of flooring and the box is 0.100. Using energy considerations, determine the final speed of the box (in m/s) after sliding across the rough section of flooring. m/s

You drop a 2.60 kg book to a friend who stands on the ground at distance D = 12.0 m below. If your friend's outstretched hands are at distance d = 1.50 m above the ground (see the figure), (a) how much work Wg does the gravitational force do on the book as it drops to her hands? (b) What is the change AU in the gravitational potential energy of the book-Earth system during the drop? If the gravitational potential energy U of that system is taken to be zero at ground level, what is U (c) when the book is released and (d) when it reaches her hands? Now take U to be 100 J at ground level and again find (e) Wg, (f) AU, (g) U at the release point, and (h) U at her hands. (a) Number i Units (b) Number i Units (c) Number i Units (d) Number i Units (e) Number i Units (f) Number i Units (g) Number i Units (h) Number i Units > > > > > > >