https://www.khanacademy.org/science/cambridge-o-level-physics-cie/x0e04e0cb682fb793:forces/x0e04e0cb682fb793:untitled-lesson-144newton-s-first-law-of-motion/v/newtons-first-law 2025-12-18T02:00:41.510401167Z Newton's first law If the forces acting on an object are balanced (the net force is zero), the object will not accelerate. It will remain at rest or moving with constant velocity. If the forces acting on object are unbalanced (the net force is not zero), the object will accelerate. Its speed and/or direction of motion will change. Mahesh Shenoy video https://cdn.kastatic.org/ka_thumbnails_cache/b3419448-c6b7-41eb-a34e-fe3cbbd247d4_1280_720_base.png Newton's first law If the forces acting on an object are balanced (the net force is zero), the object will not accelerate. It will remain at rest or moving with constant velocity. If the forces acting on object are unbalanced (the net force is not zero), the object will accelerate. Its speed and/or direction of motion will change. https://cdn.kastatic.org/ka-youtube-converted/Q0T2zjmvvA0.mp4/Q0T2zjmvvA0.mp4 366 Newton's first and second laws https://www.khanacademy.org/science/cambridge-o-level-physics-cie/x0e04e0cb682fb793:forces/x0e04e0cb682fb793:newton-s-nd-law-of-motion/v/newtons-second-law 2025-07-01T10:10:08.145512912Z Newton's second law If the forces on an object are unbalanced (the net force is not zero), the object will accelerate. How much the object accelerates depends on two factors: the strength of the net force, and the mass of the object. We can conduct an experiment to determine how acceleration depends on these two factors separately. If we keep the object's mass constant and increase the net force, we find that the object accelerates more. If we keep the net force constant and increase the object's mass, we find that the object accelerates less. Mahesh Shenoy video https://cdn.kastatic.org/ka_thumbnails_cache/6addfd09-2e8d-4bf9-94de-e47adc97ad78_1280_720_base.png Newton's second law If the forces on an object are unbalanced (the net force is not zero), the object will accelerate. How much the object accelerates depends on two factors: the strength of the net force, and the mass of the object. We can conduct an experiment to determine how acceleration depends on these two factors separately. If we keep the object's mass constant and increase the net force, we find that the object accelerates more. If we keep the net force constant and increase the object's mass, we find that the object accelerates less. https://cdn.kastatic.org/ka-youtube-converted/l_rw0RfS5x4.mp4/l_rw0RfS5x4.mp4 557 Newton's first and second laws https://www.khanacademy.org/science/ms-physics/x1baed5db7c1bb50b:motion-and-forces/x1baed5db7c1bb50b:connecting-motion-and-forces/a/forces-and-acceleration 2026-06-13T14:10:34.285337154Z Learn and try: Connecting motion and forces Use a PhET simulation to investigate the effects of balanced and unbalanced forces on an object's motion. Explore how an object's acceleration is affected by the net force acting on it and its mass. article https://www.khanacademy.org/science/cambridge-o-level-physics-cie/x0e04e0cb682fb793:forces/x0e04e0cb682fb793:newton-s-nd-law-of-motion/e/understand-newton-s-second-law 2026-06-20T14:19:59.261588707Z Understand: Newton's first and second laws Check your understanding of Newton's second law in this set of free practice questions. Emily Cizmas exercise https://www.khanacademy.org/science/cambridge-o-level-physics-cie/x0e04e0cb682fb793:forces/x0e04e0cb682fb793:newton-s-nd-law-of-motion/e/apply-newton-s-second-law 2026-01-23T20:00:36.154127952Z Apply: Newton's first and second laws Apply your knowledge of Newton's second law in this set of free practice questions. Emily Cizmas exercise