if three points charges are placed in straight line as shown below then find the net force on Q3 where?

A100 kg running back runs at 5m/s into a stationary linebacker. it takes 0.5 for the running back to be completely stopped

Sodium chloride, nacl, is formed when a sodium atom transfers its electron to a chlorine atom. the difference in charge between the two atoms creates a(n) attraction that bonds them together.

Calculate a pendulums frequency of oscillation (in hz) if the pendulum completes one cycle in 0.5s.