no 9 dan 10 sama caranya

9][
Berdasarkan rumus:
w/F = s/h
Usaha bergantung pada: berat benda, panjang bidang miring, tinggi bidang miring. 
Jadi, semua benar (D)

10][
s = 5 cm
f = 10 cm
h = 4 cm
h' = ... ?
Penyelesaian:

1/f = 1/s + 1/s'
1/10 = 1/5 + 1/s'
1/s' = 1/10 - 1/5
1/s' = 1/10 -2/10
1/s' = -1/10
s' = -10

M = ║s'/s║
M = ║-10/5║
M = 2

M = h'/h
2 = h'/4
h' = 4 x 2
h' = 8 cm (A)

CMIIW

9) D. Semua benar

10)
s = 5 cm
f = 10 cm
h = 4 cm

h' = h × f/s - f
h' = 4 × 10/5 - 10
h' = 40/-5
h' = -8 cm