An Earth satellite is in a circular orbit at an altitude of 500 km.Explain why the work done by the gravitational force actingon the satellite is zero. Using the work–energy theorem, whatcan you say about the speed of the satellite?

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 > > > > > > >

Same set-up for the conservation of energy was performed. The 5-g marble covered a horizontal distance of 40 cm from the edge of the ramp (horizontal) from an elevation of 15 cm above the ground. At what height (in cm) relative to edge of the ramp was the marble released? Use g=9.8 m/s2. Round off your answer to two decimal places.

Which do you think requires more work: moving up stairs at a slow speed (ex: walking) or moving up stairs at a fast speed (ex: running)? Explain your prediction with reference to the work equation and some past experience.