Page 126 - Physics Coursebook 2015 (A level)

Cambridge International AS Level Physics
12 a
b A boy stands on a platform of area 0.050 m2 and a manometer measures the pressure created in
Liquid of density ρ fills a cylinder of base area A and height h.
i Using the symbols provided, state the mass of liquid in the container. [1]
ii Using your answer to i, derive a formula for the pressure exerted on the base of the cylinder. [2]
a flexible plastic container by the weight W of the boy (Figure 7.22).
90
80 70
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40
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20
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0
platform area 0.050 m2
flexible plastic container
weight W
manometer
metre rule showing distances in cm
water
Figure 7.22 For End-of-chapter Question 12.
The density of water is 1000 kg m−3. Determine:
i the pressure difference between the inside of the plastic container and the atmosphere outside [2]
ii the weight W of the boy. [2]
13 Figure 7.23 shows water in a container filled to a depth of 0.50 m. The density of water is 1000 kg m−3.
0.50 m
0.30 m
Figure 7.23 For End-of-chapter Question 13.
a Calculate the pressure at X on the base of the container. [2]
b Explain why the pressure at X must be equal to the pressure at Y. [1]
c Explain why the force downwards on the base of the container is larger than the weight of the
liquid in the container. [2]
XY
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