QUIS

JAWABAN KUIS
1. Dik : m kereta = 30 kg
Jarak = 4,5 meter
µk = 0,25
Ditanyakan a. FN=...?
b. Wb=...?
c. Wc=...?
d. Wd=...?
e.∑W=...?
Jawaban
∑F = m.a
F-Fges = m.a
F = m.a + Fges
F = m.a + μs.mg
F = μs.mg
F = 0,25 x 30 x 10
F = 75 N

Wb = F.S
= 75 x 4,5
= 337,5 N
Wc = Fges.S
= μs.mg.s
= 0,25 x 30 x 10 x 4,5
= 337,5 N
Wd = m.g.s
= 30 x 10 x 4.5
= 1350 N
∑W = Wb+Wc+Wd
= 337,5+337,5+1350
= 2025 N
2. Em = Ek + Ep
Em1 = Em2
Ek1 + Ep1 = Ek2 + Ep2
½mv12 + m.g.h = ½ mv22 + m.g.h
0 + 0 = ½ 12 v22 + 12.10.2
0 = 6v22 + 240
V22 = -40
V = √-40 m/s

3. Dik : m1 = 5 gr= 0,005 kg
V1 = 1000 m/s
m2= 1+0.005 = 1,005 kg
Ditentukan v2= ....?
h = ....?
Jawaban
m1.v1 = m2.v2
0.005.1000 = 1.005. v2
V2 = (0,005×1000)/1,005
V2 = 4,97 m/s

Ekf = (mb + mk) gh
H = Ekf/(mb = mk).g
H = ½ (mb + mk) vt2/(mb + mk).g
H = ½ vt2/g
H = ½.24,75/10
H = 1,2375 m