I’ve done this before the answer is B
Based on the given, this is probably a gravitational potential energy problem (PEgrav). The formula for PEgrav is:
PEgrav = mgh
Where:
m = mass (kg)
g = acceleration due to gravity
h = height (m)
With this formula you can derive the formula for your unknown, which is mass. First put in what you know and then solve for what you do not know.

![30J=m(10)(10[tex] \frac{30}{100} =m](https://tex.z-dn.net/?f=30J%3Dm%2810%29%2810%5Btex%5D%20%5Cfrac%7B30%7D%7B100%7D%20%3Dm)
)[/tex]
Do operations that you can with what is given first.

Transpose the 100 to the other side of the equation. Do not forget that when you transpose, you do the opposite operation.
m = 0.30kg
The atmosphere absorbs most of the solar RADIATION in the atmosphere, but not all which is how we still get sun burns. :)
Answer:
0.23 s
Explanation:
First of all, let's find the time constant of the circuit:

where
is the resistance
is the capacitance
Substituting,

The charge on a charging capacitor is given by
(1)
where
is the full charge
we want to find the time t at which the capacitor reaches 90% of the full charge, so the time t at which

Substituting this into eq.(1) we find
