Asled and rider with a combined mass of 70 kg are at the top of a hill of height 9 m above the level ground below. the sled is given a push providing an initial kinetic energy of 1200 j at the top of the hill. what will be the kinetic energy of the sled and rider at the bottom of the hill, if friction can be ignored?

Estimate the kinetic energy of mars with respect to the sun as the sum of two terms, that due to its daily rotation about its axis, and that due to its yearly revolution about the sun. (assume mars is a uniform sphere with mass = 6.4×10 to the power of 23 kg, radius = 3.4×10 to the power of 6 m, rotation period = 24.7 hours, orbital period = 686 days and is 2.3×10 to the power of 8 km from the sun.)