NEWTON'S THIRD LAW: ACTION AND REACTION
2 marks · EasyTwo ice skaters push against each other and move apart on a frozen lake. Using Newton’s third law, state how the forces on each skater compare. State the direction of each force.
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Each skater experiences a force equal in size but opposite in direction. The forces are of equal magnitude, but each force pushes one skater away from the other.
Must show: Explicitly stating forces are equal in size but opposite in direction, Assigning the correct direction to each force (pushes skaters apart)
Also accept: The skaters push on each other with equal but opposite forces, causing both to move apart
Common mistakes: Saying one force is bigger than the other; Saying the forces act on the same skater
Show mark scheme and worked solution
Marking points
B1 · 1 mark · States that the forces on each skater are equal in size
B2 · 1 mark · States that the forces are in opposite directions (pushes them apart)
Worked solution
According to Newton’s third law, when the skaters push against each other, each one experiences a force equal in size but in the opposite direction. This makes them move apart from each other.