<u>Answer:</u>
2.39 kg
<u>Explanation:</u>
There is conservation of momentum here in this problem so we will use the following problem:

where the mass of the student
is 48.5 kg,
the mass of the skateboard
is
kg,
the initial speed of the student
is 4.25 m/s; and
the speed of the student and skateboard
is 4.05 m/s.
So substituting the given values in the above formula to get:





Therefore, the mass of the skateboard is 2.39 kg.
1 astronomical unit = 149597870700m
Enrico should divide distance in meters with this number.
Answer:
1 Acetaldehyde C2H4O
2 Acetamide C2H5NO
3 Acetic acid CH3COOH
4 Acetone C3H6O
Explanation: These are the only ones I know
The nature of the wave is a sinusoidaly varying wave.. the each particle of the wave moves up and down.. in the phase