Taking notes,because you can read back on what you learned
Potential energy decreases and kinetic energy increases.
Potential energy is related to the height, since the wagon is going downhill, height decreases and potential energy decreases.
Kinetic energy is related to the speed, since the wagon is speeding up, kinetic energy increases.
Answer:
The force of friction that acts on him is

Explanation:
The firefighter with an acceleration of 3m/s^2 take the gravity acceleration as 10m/s^2 isn't necessary to know the coefficient of friction just to know the force of friction:




Sole to Fk



They are attractive
They don’t depend on charge
The answer is high to low.