Quantity of Charge , Q = ne
Where n = number of electrons
e = charge on one electron = -1.6 * 10 ^-19 C.
n = 50 * 10^31 electrons
Q = (50 * 10^31)*( -1.6 * 10 ^-19 ) = -8 * 10^13 C.
Note that the minus sign indicates that the charge is a negative charge.
Since we have 15 kilometers per hour, and we're looking for 20 minutes, let's set up proportions.
20/60 minutes = x/15
20/60 = 1/3, so let's leave that simplified.
1/3 = x/15
Look at the denominators, 3 to 15 is a factor of 5, so multiply the numerator by 5.
1 • 5 = 5, so you will cover 5 kilometers in 20 minutes.
I hope this helps!
I think it's a pulley and a lever.
Answer: B. I hope you get this right.