The car at 60 kph has 9 times more kinetic energy than the car traveling at 20 kph. This assumes that both cars have the same mass. Kinetic energy depends on the square of thee speed so if one car is going 3 times faster, its kinetic energy will be 3^2 ( = 9 ) greater. The car going at 60 kph will have 4 times the KE of the car going at 30 kph ( again assuming that the cars have the same mass.)
.................yes...................
The frequency is
and it is blue light
Explanation:
The relationship between the speed, the frequency and the wavelength of an electromagnetic wave is given by:

where
is the speed of light
f is the frequency of the wave
is its wavelength
In this problem, the wavelength of the wave is

Therefore, its frequency is:

The wavelength of this wave is

And by looking at the table of the wavelengths of the colors, we notice that this corresponds to the blue light, which has a range of wavelength of
[450 - 495] nm
Learn more about waves and electromagnetic waves here:
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