Question

Bantu jawab soal nomr 7-9 saja

Answer 1

Verified answer

7.
Diketahui :
m = 2 kg
F = 20 N
tan alpha = 3/4
alpha = arctan 3/4 = 37°
W = m.g = 20 N

Ditanyakan : N = ... N

Pembahasan :
Fy = 20 sin alpha = 20 . 3/5 = 12 N

Pada sumbu y, Sigma F =0
Fy + N = W
N = W - Fy = 20 - 12 = 8 N

8.
Diketahui :
mu = 0.25

Ditanyakan : ax = ... m/s^2

Pembahasan :
Fx = F cos alpha = 20 . 4/5 = 16 N
f = mu.N = 0.25 . 8 = 2 N

Pada sumbu x, F = m.ax
Fx - f = m.ax
16-2 = 2.ax
ax = 14/2 = 7 m/s^2

9.
Diketahui :
alpha = 30°
F = 40 N
m = 5 kg
Vo = 0 m/s
t = 2 s

Ditanyakan : v = ... m/s

Pembahasan :
Sisi miring bidang sebagai sumbu x
F - Wx = m.a
40 - m.g.sin 30° = 5.a
40 - 50/2 = 5.a
40 - 25 = 5.a
8 - 5 = a
a = 3 m/s^2 sejajar bidang miring

v = Vo + a.t = 0 + 3.2 = 6 m/s
Note : pemberian gaya dianggap konstan / terus menerus

Answer 2

Verified answer

7][
m = 2 kg
F = 20 N, tan α = ¾
g = 10 m/s²
N = __?

ΣFy = 0
N + F sin α - w = 0
N = w - F sin α
N = 2 • 10 - 20 • (3/5)
N = 20 - 12
N = 8 N ← jwb


8][
μₖ = ¼
a = __?

ΣFx = m a
F cos α - fₖ = m a
20 • (4/5) - ¼ • 8 = 2 a
16 - 2 = 2 a
a = 7 m/s² ← jwb


9][
bidang miring licin
α = 40°
m = 5 kg
g = 10 m/s²
F = 40 N sejajar bid. miring ke atas
t = 2 s
Vt = __?

percepatan
ΣF = m a
F - mg sin α = m a
40 - 5 • 10 • ½ = 5 a
40 - 25 = 5 a
a = 3 m/s²

kecepatan
Vt = Vo + a t
Vt = 0 + 3 • 2
Vt = 6 m/s ← jwb