They repeated it 5 times because they wanted to see if the answer they got was correct. by doing that they are checking if each time it’s the same
The wavelength will chang along with the frequency, I think. I don't recall why it would lose energy...
Refer to the diagram shown below.
u = 20 m/s, the horiontal launch velocity
v = 0, initial vertical velocity
Assume that wind resistance may be ignored.
The time, t, of the flight is given by
(1/2)*(9.8 m/s²)*t² = (100 m)
t² = 100/4.9 = 20.4082
t = 4.5175 s
Th horizontal distance traveled is
d = (20 m/s)*(4.5175 s) = 90.35 m
Answer: B
The projectile hits the ground at approximately 90 m from the base of the cliff.
The quantum mechanical model describes the allowed energies an electron can have. It also describes how likely it is to find the electrons in various locations around an atom's nucleus.