A baseball is thrown with a speed of 36 meters per second (m/s). What is the distance from the mound to home plate if the ball takes 0.5 seconds to leave the pitcher's hand
and cross the plate?
72 meters
41 meters
31 meters
18 meters

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)