A 3.0 g copper penny has a positive charge of 42 microC. What fraction of its electrons has it lost?

You throw a baseball directly upward at time t = 0 at an initial speed of 12.3 m/s. what is the maximum height the ball reaches above where it leaves your hand? at what times does the ball pass through half the maximum height? ignore air resistance and take g = 9.80 m/s2.

To do work, this truck uses energy stored in chemical fuel and an electrical battery. how much total energy does this truck put out?

With i really need the correct answer!