Which principle states that motion persists unless acted upon by a net external force?

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Multiple Choice

Which principle states that motion persists unless acted upon by a net external force?

Inertia is the tendency of objects to resist changes in their motion. Newton's first law states that an object at rest stays at rest and a moving object keeps moving in a straight line at a constant speed unless a net external force acts on it. So, if nothing pushes or slows it down, a moving object will maintain its motion; if nothing pushes it, a stationary object won't start moving. This explains everyday observations like a hockey puck gliding on ice gradually slowing due to friction, or a parked car staying put until someone pushes. Other ideas like conservation of energy, gravity, or buoyancy describe different physical relationships, not how motion persists in the absence of net forces.

Inertia is the tendency of objects to resist changes in their motion. Newton's first law states that an object at rest stays at rest and a moving object keeps moving in a straight line at a constant speed unless a net external force acts on it. So, if nothing pushes or slows it down, a moving object will maintain its motion; if nothing pushes it, a stationary object won't start moving. This explains everyday observations like a hockey puck gliding on ice gradually slowing due to friction, or a parked car staying put until someone pushes. Other ideas like conservation of energy, gravity, or buoyancy describe different physical relationships, not how motion persists in the absence of net forces.

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