1) Billy bought 1 board game, 2 action figules and 1 toy car at the toy store. The board game cost $5.85, the action figures cost $4.45 a piece and the toy car was $5.15. If he paid with a twenty dollar bill, how much change should she
get back?

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.)