<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.
Teacher -> teach the topic
Learner -> learn the topic
Is that what you’re asking?
Cuz its slow for like to power the tv with water it will take about 2 days to turn on
Nonononononononononononononononononono
Answer:
total amount of fluoride 3.6 *10^6 g
Explanation:
we know that
volume of reservoir 
=![\pi* [\frac{4.70*10^2}{2}]^2 *14.2](https://tex.z-dn.net/?f=%5Cpi%2A%20%5B%5Cfrac%7B4.70%2A10%5E2%7D%7B2%7D%5D%5E2%20%2A14.2)
= 2.25*10^6 m^3
denso=ity of water = 1000 kg/m3
mass of water = 1000*2.25*10^6
= 2.25*10^9 kg = 2.25*10^12 g
fluoride 1.6 ppm
total amount of fluoride 
= 3.6 *10^6 g