New World American PVT School
Name:.......................................................................................... Grade: 10
Subject: Physics
Topic: Buoyant Force
‫مدرسة العالم الجديد األمريكية الخاصة‬
Section:..........
Date:...................................
Question 1:
Write the letter of the correct answer in the space provided.
____ 1. Which of the following is a fluid at room temperature?
a. oil
b. wood
c. lead
d. aluminum
____ 2. Which of the following statements is correct?
a. Liquids have a definite shape.
b. Gases have a definite volume.
c. Gases have a definite shape.
d. Liquids have a definite volume.
____ 3. What is true about the volume of displaced fluid for an object that is completely
submerged?
a. The volume of displaced fluid is equal to the object’s volume.
b. The volume of displaced fluid is less than the object’s volume.
c. The volume of displaced fluid is greater than the object’s volume.
d. The volume of displaced fluid is not related to the object’s volume.
____ 4. If an object weighing 50.0 N displaces a volume of water with a weight of 10.0 N,
what is the buoyant force on the object?
a. 60.0 N
b. 50.0 N
c. 40.0 N
d. 10.0 N
____ 5. Which of the following statements is true about the buoyant force on an object
that is floating on the surface of a lake?
a. The buoyant force is greater than the weight of the object.
b. The buoyant force is equal to the weight of the fluid displaced.
c. The buoyant force is the same as when the object is completely submerged.
d. The buoyant force is less than the density of the water.
____ 6. In which of the following situations will an object sink?
a. The mass density of the object is less than the mass density of the fluid.
b. The buoyant force on the object is equal to the weight of the object.
c. The mass density of the fluid is less than the mass density of the object.
d. The weight of the fluid displaced equals the weight of the object.
New World American PVT School
‫مدرسة العالم الجديد األمريكية الخاصة‬
____ 7. An uncooked egg sinks in fresh water but floats in salt water. Which of the
following expressions about the egg’s density (egg) with respect to the density of
fresh water (fw) and the density of salt water (sw) is correct?
a. egg < fw < sw
c. fw < egg < sw
b. sw < egg < fw
d. fw < sw < egg
____ 8. Which statement about an object placed in water is correct?
a. The apparent weight is always less than the weight of the object in air.
b. The apparent weight is always equal to the weight of the fluid displaced.
c. The apparent weight is never equal to zero.
d. The apparent weight is never greater than the buoyant force.
_________________________________________________________
Question 2:
Define:
Buoyant Force:
Mass Density:
New World American PVT School
Name:.......................................................................................... Grade: 10
Subject: Physics
Topic: Buoyant Force
‫مدرسة العالم الجديد األمريكية الخاصة‬
Section:..........
Date:...................................
Question 1:
Explain why water as ice is not a fluid but water as a liquid or steam is a fluid.
____________________________________________________________________________
____________________________________________________________________________
____________________________________________________________________________
____________________________________________________________________________
Question2:
State Archimedes’ Principle
Question 3:
Calculate the buoyant force on a cube of metal with an edge of 1.3 cm that is placed in salt
water. The density of the metal is 7.86  103 kg/m3, and the density of the salt water is
1.025  103 kg/m3.
New World American PVT School
Name:.......................................................................................... Grade: 10
Subject: Physics
Topic: Buoyant Force
‫مدرسة العالم الجديد األمريكية الخاصة‬
Section:..........
Date:...................................
1. The heaviest pig ever raised had a mass of 1158 kg. Suppose you placed this pig on a
raft made of dry wood. The raft completely submerged in water so that the raft’s top
surface was just level with the surface of the lake. If the raft’s volume was 3.40 m3,
what was the mass of the raft’s dry wood? The density of fresh water is 1.00  103
kg/m3.
2. La Belle, one of four ships that Robert La Salle used to establish a French colony late
in the seventeenth century, sank off the coast of Texas. The ship’s well-preserved
remains were discovered and excavated in the 1990s. Among those remains was a
small bronze cannon, called a minion. Suppose the minion’s total volume is 4.14 
102 m3. What is the minion’s mass if its apparent weight in sea water is 3.115  103
N? The density of sea water is 1.025  103 kg/m3.
New World American PVT School
‫مدرسة العالم الجديد األمريكية الخاصة‬
3. William Smith built a small submarine capable of diving as deep as 30.0 m. The
submarine’s volume can be approximated by that of a cylinder with a length of 3.00
m and a cross-sectional area of 0.500 m2. Suppose this submarine dives in a
freshwater river and then moves out to sea, which naturally consists of salt water.
What mass of fresh water must be added to the ballast to keep the submarine
submerged? The density of fresh water is
1.000  103 kg/m3, and the density of sea water is 1.025  103 kg/m3.
4. The largest iceberg ever observed had an area of 3.10  104 km2, which is larger than the
area of Belgium. If the top and bottom surfaces of the iceberg were flat and the thickness
of the submerged part was 0.84 km, how large was the buoyant force acting on the
iceberg? The density of sea water equals
1.025  103 kg/m3.