Use the equation from week 3: f
r
e
q
u
e
n
c
y
=
w
a
v
e
s
p
e
e
d
w
a
v
e
l
e
n
g
t
h
and the wavelength you found in #3 to calculate the frequency of this photon (remember the speed of light is 3E8 m/s):

that would be because of both gravity and friction. so     c

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going   so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me