Newton's 3rd Law EX 1

The diagram shows all the action-reaction pairs:

Force	Action-reaction pair
Gravity	$F_{G}$ $_{EP}$ The gravitational force exerted by the Earth on the puck	$F_{G}$ $_{PE}$ the gravitational force exerted by the puck on the Earth
Normal force	$F_{N}$ $_{IP}$ The normal force exerted by the ice on the puck	$F_{N}$ $_{PI}$ The normal force exerted by the puck on the ice
Force of friction	$F_{f}$ $_{IP}$ The force of friction exerted by the ice on the puck	$F_{f}$ $_{PI}$ The force of friction exerted by the puck on the ice

The magnitude of $F_{G}$ $_{EP}$ is 3 N (0.3 kg x 10 N/kg) and the magnitude of $F_{G}$ $_{PE}$ is also 3 N.

The magnitude of $F_{N}$ $_{PI}$ is 3 N and the magnitude of $F_{N}$ $_{IP}$ is also 3 N.

The magnitude of $F_{f}$ $_{PI}$ is 0.06 N and the magnitude of $F_{f}$ $_{IP}$ is also 0.06 N.

Important note: Even though $F_{G}$ $_{EP}$ and $F_{N}$ $_{IP}$ are equal and opposite forces, they are not an action-reaction pair!