Can someone help me with these two Physics questions?
1. A particle of mass m and charge q is dropped from the height of h towards a point charge Q, which lies on the ground. What is the minimum distance between the charges? Your should be in terms of m, q, Q, h, g) (5 marks)
Hint: Use conservation of energy
2. Point charges Q and -2Q are at a distance d. At what distances from Q is the electric potential zero? Only consider the points on the line that connects Q1 and Q2.