SUVAT Sign Kesalahan That Flip Your Jawaban
Constant-percepatan equations only usaha if you pick one positive direction and stick to it. These traps show where signs usually go wrong.
v = u + at · s = ut + ½at² · v² = u² + 2as — Pick one positive axis for the whole problem
Jebakan 1: Treating every slowdown as “a is negative” without a defined axis
Salah: Car slows from 20 m/s to 10 m/s → student writes a = −5 without saying which way is positive.
Benar: If forward is positive and the car slows while moving forward, a is negative. State the axis first.
Perbaikan: Negative percepatan means kecepatan is becoming less positive — not always “going backward.”
Jebakan 2: Using path length as perpindahan s
Salah: Walk 4 m forward and 1 m back → put s = 5 m into SUVAT.
Benar: Perpindahan is net change: s = +3 m if forward is positive. Jarak traveled is 5 m.
Perbaikan: SUVAT uses perpindahan s, not total path length.
Jebakan 3: Dropping signs inside v² = u² + 2as
Salah: u = +12, a = −3, s = +16 → computing as if everything were positive magnitudes only.
Benar: Keep signed values: v² = (12)² + 2(−3)(16) = 144 − 96 = 48 → |v| = √48.
Perbaikan: Square roots give ±v; the sign of v comes from the physical direction you chose.
Jebakan 4: Jatuh bebas with inconsistent up/down signs
Salah: Taking up as positive for u but down as positive for g dalam the same line.
Benar: If up is positive, g ≈ −9.8 m/s². If down is positive, g ≈ +9.8 m/s². One choice only.
Perbaikan: Tulis “up positive” or “down positive” at the top of the usahaing.
Jebakan 5: Using a SUVAT equation that needs a missing variable
Salah: Known u, v, t — but using s = ut + ½at² without finding a first (or picking the equation that omits a).
Benar: Gunakan s = ½(u + v)t when a is unknown, or find a = (v − u)/t first.
Perbaikan: List knowns, then pick the equation that does not need the missing symbol.
Kesimpulan
Pilih one positive direction, write it down, and keep every u, v, a, and s consistent with that choice.
FAQ
Does negative percepatan always mean the benda is going backward?
No. It means kecepatan is decreasing along your positive axis. The benda can still be moving forward while slowing down.
Is perpindahan the same as distance?
No. Perpindahan is net position change (signed). Jarak is path length (≥ 0).
Latihan a = Δv/t · Latihan v = d/t · Kinematika Kalkulator · Percepatan Kalkulator · Perpindahan Kalkulator · Kecepatan Kalkulator
a = Δv/t Rumus Latihan · v = d/t Rumus Latihan · Choosing the Right Kinematika Equation · Cara menghitung Percepatan