A 500 g mass is tied to a string and swung in a horizontal circle with a radius of 40 cm. The speed of the mass is held constant, and the period of rotation is 0.7 s. What is the speed of the mass

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)