Which is the best example of the law of conservation of energy? O A basketball stops bouncing because its energy disappears.
A rolling skateboard slows down because some of its kinetic energy changes to heat.
O A falling book hits the ground and all of its energy is destroyed.
A toy car gains speed as it moves down a ramp because the ramp creates energy.

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.)