계산 방법 힘 (F = ma): Newton’s Second Law

계산 힘 with F = ma. Net 힘 vs 무게, rearrangements, unit traps, 일ed examples, and a free 힘 calculator.

What 힘 Asks

Newton’s second law says net 힘 equals 질량 times 가속도. The same push that barely moves a heavy crate can send a light cart flying — 질량 sets how much 가속도 you get for a given 힘.

The core 공식 is F = ma. 질량 m in kilograms times 가속도 a in m/s² gives 힘 in newtons (N). One newton is the 힘 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 힘 calculator first, then return here for net 힘, 무게, and links to related tools.

The 공식s

  • F = ma — net 힘 from 질량 and 가속도.
  • a = F / m — rearrange for 가속도.
  • m = F / a — rearrange for 질량.
  • 무게 near Earth: W = mg (a special case of F = ma with a = g).

    • F in F = ma is the net 힘 — the vector sum of all 힘s after you cancel or combine them on a free-body diagram. A single push is not always the net 힘.

    Net 힘 vs Named 힘s

    마찰, tension, normal 힘, and gravity are separate 힘s. You add them (with signs) to get F_net, then F_net = ma.

    Sliding 저항: friction Ff = μN. 지원 from a surface:

    normal 힘 N = mg or mg cosθ.

    Circular paths need inward 힘 F = mv²/r — see centripetal 힘.

    힘, 운동량, and 일

    충격량 links 힘 to 운동량 change: J = FΔt = Δp. See 운동량 and p = mv.

    힘 through a distance does 일: W = Fd. See the 일 calculator.

    단위

  • m → kg (convert grams first).
  • a → m/s².
  • F → newtons (N).
  • Do not mix 무게 in newtons with 질량 in kilograms inside F = ma.

    • 풀이 예제

    예제 1: 4.0 kg at 2.5 m/s²

    F = ma = (4.0)(2.5) = 10 N in the direction of 가속도.

    예제 2: find 가속도

    F = 36 N, m = 6.0 kg. a = F/m = 36/6.0 = 6.0 m/s².

    예제 3: find 질량

    F = 24 N, a = 3.0 m/s². m = F/a = 24/3.0 = 8.0 kg.

    예제 4: 무게

    m = 5.0 kg, g = 9.8 m/s². W = mg = 49 N downward. That is the gravitational 힘, not a separate “kind” of F = ma.

    흔한 실수

  • Using grams in F = ma without converting to kilograms.
  • Treating one applied 힘 as F_net when friction or other 힘s act.
  • Confusing 질량 (kg) with 무게 (N).
  • Forgetting that F and a point the same way for the net-힘 direction.

    • 확인 It on the 계산기

    힘 calculator — F = ma.

    가속도 calculator.

    마찰 calculator.

    운동량 calculator.

    학습 F = ma and confirm every home일 number on the calculator.

    문서

    • 탄성 위치 에너지 공식 (U = ½kx²): 계산기 & 예제
    • 계산 방법 전기 전력 (P = VI, I²R, V²/R)
    • 계산 방법 파동 속도 (v = fλ): 주파수 × 파장
    • 계산 방법 무게 (W = mg): 질량 vs 힘
    • 계산 방법 밀도 (ρ = m/V): 질량 ÷ Volume
    • 계산 방법 가속도 (a = (v − u)/t)

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