Problem 1: I need you to check the first problem. The answer makes me think I may have done something wrong. 1) A quantity of water equal to 2.5 x 10^10 cc falls from a rain cloud that is 1000 m high. If this rain falls in just 1 hour, how much power is generated? The formula I used was p = F x d/t and my answer ended up being 66,666,666.67 N*m/sec, or 66,666,666.67 watts. Problem 2: 2) The mass of an electron is 9 x 10^-31 kg. The mass of a proton is 1.7 x 10^-27 kg. The proton and electron are about 1.0 x 10^-10 m apart in a hydrogen atom. What force of gravitation exists between the proton and the electron of the hydrogen atom? What is the CENTRIPETAL acceleration of the electron? Using Gm1m2/r2, I figured the force of gravitation to be 1.02 x 10^-47 N. However, I have no idea how to calculate the CENTRIPETAL acceleration. Also, am I right on the force of gravitation? Problem 3: 3) The end of the lever of a tire jack travels 7 m for every centimeter that it lifts the car. If the car has a mass of 1000 kg and a force of 50 N is needed to lift the car, what is the efficiency of the jack? Here is what I have so far and am stuck: work done to lift car = F x d (work output) (1000 kg)(9.8 N/kg) = 9800 N winput = F2(pie)r (50N)(2)(3.14)(3.5m) = 1099 N*m woutput = 9800 N x ... ???