CHAPTER 13
1. How tall must a column of mercury,
ρ 1.36 104 kg/m3, be to exert a
pressure equal to the atmosphere?
2. A dog, whose paw has an area of
12.0 cm2, has a mass of 8.0 kg. What
average pressure does the dog exert while
standing?
3. A crate, whose bottom surface is 50.4 cm
by 28.3 cm, exerts a pressure of
2.50 103 Pa on the floor. What is the
mass of the crate?
4. The dimensions of a waterbed are 2.13 m
by 1.52 m by 0.38 m. If the frame has a
mass of 91.0 kg and the mattress is filled
with water, what pressure does the bed
exert on the floor?
5. A rectangular block of tin,
ρ 7.29 103 kg/m3, has dimensions of
5.00 cm by 8.50 cm by 2.25 cm. What
pressure does it exert on a table top if it is
lying on its side of
a. greatest surface area?
b. smallest surface area?
6. A rowboat, mass 42.0 kg, is floating on a
lake.
a. What is the size of the buoyant force?
Copyright © by Glencoe/McGraw-Hill
b. What is the volume of the submerged
part of the boat?
7. A hydraulic lift has a large piston of
20.00-cm diameter and a small piston of
5.00-cm diameter. What is the
mechanical advantage of the lift?
Physics: Principles and Problems
8. A lever on a hydraulic system gives a
mechanical advantage of 5.00. The crosssectional area of the small piston is
0.0400 m2, and that of the large piston is
0.280 m2. If a force of 25.0 N is exerted
on the lever, what is the force given by
the larger piston?
9. A piece of metal weighs 75.0 N in air and
60.0 N in water. What is the density of
the metal?
10. A river barge with vertical sides is 20.0 m
long and 10.0 m wide. It floats 3.00 m
out of the water when empty. When
loaded with coals the water is only 1.00
m from the top. What is the weight of
the load of coal?
11. What is the change in the length of a
15.0-m steel rail as it is cooled from
1535°C to 20°C?
12. A concrete sidewalk section 8.000 m by
1.000 m by 0.100 m at exactly 0°C will
expand to what volume at 35°C?
13. An air-filled balloon of 15.0-cm radius at
11°C is heated to 121°C. What change in
volume occurs?
14. A circular, pyrex watch glass of 10.0-cm
diameter at 21°C is heated to 501°C.
What change will be found in the
circumference of the glass?
15. A 200.0-cm copper wire and a 201-cm
platinum wire are both at exactly 0°C. At
what temperature will they be of equal
length?
Supplemental Problems
21