Lesson: Newton’s Third Law of Motion Physics • First Year of Secondary School

Students will be able to

• understand that Newton’s third law of motion applies to pairs of objects rather than to individual objects,
• understand that all forces are forces between two interacting objects,
• understand that forces between two interacting objects always occur in pairs,
• recall that pairs of objects exert equal magnitude forces on each other,
• recall that the forces exerted by a pair of objects on each other act in opposite directions,
• recall that a pair of forces consistent with Newton’s third law must be of the same type (such as gravitational or electromagnetic),
• recall that some of the forces that pairs of objects exert on each other act only during contact and some others act without requiring contact,
• recall that the forces that pairs of objects exert on each other can be mutually attracting or mutually repelling; gravitational forces can only attract but electromagnetic forces can either attract or repel.