Physics · Grades 7–10
Balanced forces and inertia · Revision sheet
Recognize that zero net force does not require zero velocity.
Learn the idea
Net force
Combine all forces on the same object as vectors. Equal opposite forces on that object can cancel.
Inertia
With zero resultant force, an object remains at rest or continues in uniform straight-line motion in an inertial frame.
Friction
Real moving toys often slow because a force acts, not because motion uses up an internal supply of force.
Object boundary
Do not cancel a force on one object against a force on a different object when finding a resultant.
Explain without looking
- An object has 15 N right and 6 N left. Find the right-positive net force.
- A learner draws a forward arrow labelled motion as an extra force. What should be checked?
Further reading and review references
These are reference links, not copied exercises, institutional endorsement or proof of independent review.
Independent educational review required. Grade bands are approximate; these are not officially aligned curricula.