Radar consists of electromagnetic waves. a warplane is rendered invisible to enemy radar by applying an antireflective polymer coating. if radar waves have a frequency of 10 ghz (giga = 1e9), and the index of refraction of the polymer for these waves is 1.50, what is the minimum thickness of the antireflective coating? (c = 3e8 m/s. the index of refraction of air is ~1, and that of the fuselage is larger than for the polymer coating)

Awater balloon launcher uses an elastic band with a spring constant of 115 n/m to use thee launcher you stretch thee band back with a balloon n it the water balloons have a mass of 1.3 kg a) if you stretch the band by 0.8 m, what elastic force will the band exert? b) with the band stretched 0.8 m, how much elastic potential energy is stored in the spring? c) if you release the band, it pushes forward. what is the kinetic energy of the balloon when it reaches the natural length of the band? d) what is the speed of the balloon when it reaches the natural length of the band?