The engineer applies brakes, and the train comes to a complete stop in half a mile (800 m) without hitting the car. There is a gradual descent of the track, and the point where the train stops is 10 m lower than the point where brakes were first applied. What was the average friction force acting on the train during braking?

(2) (a) you have a simple circuit that consists of only a battery (δvbat=1.5v) and two resistors with resistance r1=10ω and r2=5ω, connected in series with each other. what is the current running through the battery? (b) you re-arrange your circuit so now r2 is attached in parallel to r1 rather than in series. what is the current running through the battery? (c) you add an additional resistor r3=7ω on the same branch as r2. what is the current running through the battery? (d) what is the power dissipated in r3?

This is for my 8th grade science class, i really don’t understand. can someone me? , lol.

The strong nuclear force acts over a small distance than the electrostatic force. true or false