Q1. A 2.5g copper penny is given a charge of -0.50 mC.
How many excess electrons make up this charge?
What is the percentage of the mass of these excess electrons to the mass of the penny?
Q2. A proton is travelling to the right at. It has a head-on perfectly elastic collision with a carbon atom. The mass of the carbon atom is 12 times the mass of the proton. What are the speeds of each after the collision? What is the direction of the proton after the collision? What is the direction of the carbon atom after the collision?