Acat with a mass of 4.50 kilograms sits on a ledge 0.800 meters above the ground. if it jumps to the gground, how much kinetic energy will it have just as it reaches the ground?

The atoms in a nickel crystal vibrate as harmonic oscillators with an angular frequency of 2.3 × 1013 rad/s. the mass of a nickel atom is 9.75 × 10-26 kg. what is the difference in energy between adjacent vibrational energy levels of nickel? (h = 6.626 × 10-34 j • s, , 1 ev = 1.60 × 10-19 j)