Phys101
Term:131
Online HW-Ch14-Lec01
Q1:
The pressure exerted on the ground by a man is greatest when:
A.
B.
C.
D.
E.
he stands with both feet flat on the ground
he stands flat on one foot
he stands on the toes of one foot
he lies down on the ground
all of the above yield the same pressure
Ans:
C
Q2:
A uniform U-tube is partially filled with water. Oil, of density 0.75 g/cm3, is poured
into the right arm until the water level in the left arm rises h 1 = 3.0 cm (see Fig 8).
The length of the oil column (h) is then:
Ans:
PL = PR
ρw gh1 = ρ0 gh
ρw
1 g/cm3
h=
h =
× 3 cm
ρ0 1
0.75 g/cm3
PL
PR
h = 4.0 cm
Q3:
A hydraulic press has one piston of diameter 2.0 cm and the other piston of diameter
8.0 cm. What force must be applied to the smaller piston to obtain a force of 1600N at
the larger piston?
Fs A s
Ans:
FS FL
AL
=
AS AL
ds 2
FS = π 2 ∙ π
4
4 dL
FL
FS = FL �
FL = 1600 N
ds 2
2 2
� = 1600 × � � = 100 N
dL
8
KFUPM-Physics Department
1