You're on a roof top and throw a ball downward to the ground below, and another upward whereupon after rising, it falls and also strikes the ground below. If your downward and upward initial speeds are the same, how do the speeds of the balls compare upon striking the ground? Explain in terms of energy.

If the speed of a particle triples ,by what factor does its kinetic energy increase?

30 points - when can a theory be modified if a new type of technology allows for new observations that raise new questions? a. immediately, while the questions about the theory are being asked b. after new hypotheses related to the theory are tested in experiments c. only after the new observations disprove all parts of the theory d. while scientists begin to think about how the theory could improve

Henry, whose mass is 95 kg, stands on a bathroom scale in an elevator. the scale reads 830 n for the first 2.4 s after the elevator starts moving, then 930 n for the next 2.4 s. part a what is the elevator's speed 4.8 s after starting? express your answer with the appropriate units.