A projectile is fired with an initial speed of 1000 m/s at an angle of 37° above the horizontal. If air resistance is neglected, the horizontal component of the projectile's
velocity after 20 s is approximately
Select one
A 800
B 160
C 640
D 40
E 600​

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)