Summary

• Density
• Pressure in fluids
• Pascal's principle

• Bonus Question Ch.13





• Archimedes' principle
• buoyant forces
• sinking: object displaces its volume
• floating: object displaces its mass
• animated applet
• apparent weight applet
Example #1
Example #2

• PhET applet



   


• Practice questions

Example #3a
Example #3b
Example #3c
Example #3d
Example #3e
Example #3f

Example #4

Example #5

klm
The mass of Venus is 80% that of the earth while its radius is 95% that of the earth. What is the value of the acceleration due to gravity on Venus? (Use g_Earth = 9.80 m/s²).
A. 8.25 m/s²
B. 8.69 m/s²
C. 11.1 m/s²
D. 11.6 m/s²
Answer



















klm
What is the buoyant force on a submerged anchor that has a volume of 0.500 m³? The density of water is 1000 kg/m³.
A. 4900 N
B. 490 N
C. zero
D. Need anchor's density
Answer



















PoP5 15.34mod
About how many 0.125-m radius, 5.00-gram helium balloons do you need to get airborne? ρ_air = 1.29 kg/m³ and ρ_He = 0.179 kg/m³. Assume your mass is 70.0 kg.
A. 200
B. 2,000
C. 20,000
D. 200,000
Answer



















 
A block of wood, density 0.45 g/cm³, floats in water. If it's a cube measuring 10 cm on a side, what is its mass?
A. 0.0045 kg
B. 0.045 kg
C. 0.45 kg
D. 4.5 kg
Answer



















 
What is the net force on the block of wood?
A. zero
B. 4.41 N
C. 441 N
D. 22.0 N
Answer



















 
What is the buoyant force on the block?
A. zero
B. 4.41 N
C. 441 N
D. 22.0 N
Answer



















 
What is the weight of the displaced water?
A. 441 N
B. 22.0 N
C. 5.39 N
D. 4.41 N
Answer



















 
What is the volume of the displaced water?
A. 4.50 cm³
B. 450 cm³
C. 22.2 cm³
D. 0.00222 cm³
Answer



















 
How deep does the block sink into the water?
A. zero cm
B. 4.5 cm
C. 5.5 cm
D. 10 cm
Answer



















 
A metal box is 4.00 cm wide, 8.00 cm long, and 3.00 cm high. If it has a mass of 64 g, how deep will it sink into water?
A. 0.67 cm
B. 1.00 cm
C. 1.50 cm
D. 2.00 cm
Answer



















 
A ball has a volume of 5.0 cm³ and a mass of 20 g. What will the ball's apparent mass be under water?
A. 5.0 g
B. 10 g
C. 15 g
D. 20 g
Answer







































answer

B. 8.69 m/s²




















answer

A. 4900 N




















answer

C. 20,000




















answer

C. 0.45 kg




















answer

A. zero
By Newton's Second Law, since it is not accelerating.



















answer

B. 4.41 N




















answer

D. 4.41 N
By Archimedes' principle the weight of the displaced water equals the buoyant force.



















answer

B. 450 cm³




















answer

B. 4.5 cm




















answer

D. 2.00 cm




















answer

C. 15 g