كيفية الحساب القوة (F = ma): Newton’s Second Law
احسب force with F = ma. Net force vs weight, rearrangements, unit traps, worked examples, and a free force calculator.
What القوة Asks
Newton’s second law says net force equals mass times acceleration. The same push that barely moves a heavy crate can send a light cart flying — mass sets how much acceleration you get for a given force.
The core formula is F = ma. الكتلة m in kilograms times acceleration a in m/s² gives force in newtons (N). One newton is the force that accelerates 1 kg at 1 m/s²: 1 N = 1 kg·m/s².
If you already have m and a (or F and one unknown), open the free force calculator first, then return here for net force, weight, and links to related tools.
The الصيغةs
F in F = ma is the net force — the vector sum of all forces after you cancel or combine them on a free-body diagram. A single push is not always the net force.
Net القوة vs Named القوةs
الاحتكاك, tension, normal force, and gravity are separate forces. You add them (with signs) to get F_net, then F_net = ma.
Sliding resistance: friction Ff = μN. Support from a surface:
normal force N = mg or mg cosθ.
Circular paths need inward force F = mv²/r — see centripetal force.
القوة, الزخم, and الشغل
Impulse links force to momentum change: J = FΔt = Δp. See momentum and p = mv.
القوة through a distance does work: W = Fd. See the work calculator.
Units
الشغلed Examples
Example 1: 4.0 kg at 2.5 m/s²
F = ma = (4.0)(2.5) = 10 N in the direction of acceleration.
Example 2: find acceleration
F = 36 N, m = 6.0 kg. a = F/m = 36/6.0 = 6.0 m/s².
Example 3: find mass
F = 24 N, a = 3.0 m/s². m = F/a = 24/3.0 = 8.0 kg.
Example 4: weight
m = 5.0 kg, g = 9.8 m/s². W = mg = 49 N downward. That is the gravitational force, not a separate “kind” of F = ma.
أخطاء شائعة
Check It on the Calculator
القوة calculator — F = ma.
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