Four 15 Ω resistors are connected in series with a 45 V battery. What is the current in the circuit?

The earth is constantly spinning on its axis, like you might spin a basketball on your finger. it is this spinning of the earth that causes

Could someone me find the answer to this problem.

Cathy is pedaling down a steep hill on her bicycle and wants to be able to coast up the next hill, which is 25 meters high, without pedaling. cathy and her bicycle have a mass of 75 kg. assuming her bicycle is 100% efficient, what would her speed have to be?