1. D. one-quarter the density. E. one-eighth the density.
The sphere on the right has twice the mass and twice the radius of the sphere on the left. Compared to the sphere on the left, the larger sphere on the right has
mass m radius R
mass 2m radius 2R
A. twice the density.
B. the same density.
C. half the density.
D. one-quarter the density.
E. one-eighth the density.
Answer: D

2. A12.1
The sphere on the right has twice the mass and twice the radius of the sphere on the left. Compared to the sphere on the left, the larger sphere on the right has
mass m radius R
mass 2m radius 2R
A. twice the density.
B. the same density.
C. half the density.
D. one-quarter the density.
E. one-eighth the density.

3. A. The block of ice experiences the greatest buoyant force.
Q12.2
A block of ice (density 920 kg/m3), a block of concrete (density 2000 kg/m3), and a block of iron (density 7800 kg/m3) are all submerged in the same fluid. All three blocks have the same volume. Which block experiences the greatest buoyant force?
A. The block of ice experiences the greatest buoyant force.
B. The block of concrete experiences the greatest buoyant force.
C. The block of iron experiences the greatest buoyant force.
D. All three experience the same buoyant force.
E. The answer depends on the density of the fluid.
Answer: D

4. A12.2
A block of ice (density 920 kg/m3), a block of concrete (density 2000 kg/m3), and a block of iron (density 7800 kg/m3) are all submerged in the same fluid. All three blocks have the same volume. Which block experiences the greatest buoyant force?
A. The block of ice experiences the greatest buoyant force.
B. The block of concrete experiences the greatest buoyant force.
C. The block of iron experiences the greatest buoyant force.
D. All three experience the same buoyant force.
E. The answer depends on the density of the fluid.

5. A. increases by more than 1000 Pa. B. increases by 1000 Pa.
Q12.3
A cylinder is completely filled with water. The top of the cylinder is sealed with a tight-fitting lid. If you push down on the lid with a pressure of 1000 Pa, the water pressure at the bottom of the cylinder
A. increases by more than 1000 Pa.
B. increases by 1000 Pa.
C. increases by less than 1000 Pa.
D. is unchanged.
E. increases by an amount determined by the height of the cylinder.
Answer: B

6. A12.3
A cylinder is completely filled with water. The top of the cylinder is sealed with a tight-fitting lid. If you push down on the lid with a pressure of 1000 Pa, the water pressure at the bottom of the cylinder
A. increases by more than 1000 Pa.
B. increases by 1000 Pa.
C. increases by less than 1000 Pa.
D. is unchanged.
E. increases by an amount determined by the height of the cylinder.

7. A. a greater pressure and a greater volume flow rate.
Q12.4
An incompressible fluid with zero viscosity flows through a pipe of varying radius (shown in cross-section). Compared to the fluid at point P, the fluid at point Q has P Q
radius R
radius 2R
A. a greater pressure and a greater volume flow rate.
B. a greater pressure and the same volume flow rate.
C. the same pressure and a greater volume flow rate.
D. a lower pressure and the same volume flow rate.
E. none of the above.
Answer: D

8. A12.4
An incompressible fluid with zero viscosity flows through a pipe of varying radius (shown in cross-section). Compared to the fluid at point P, the fluid at point Q has P Q
radius R
radius 2R
A. a greater pressure and a greater volume flow rate.
B. a greater pressure and the same volume flow rate.
C. the same pressure and a greater volume flow rate.
D. a lower pressure and the same volume flow rate.
E. none of the above.

9. A. four times the fluid speed. B. twice the fluid speed.
Q12.5
An incompressible fluid with zero viscosity flows through a pipe of varying radius (shown in cross-section). Compared to the fluid at point P, the fluid at point Q has P Q
radius R
radius 2R
A. four times the fluid speed.
B. twice the fluid speed.
C. the same fluid speed.
D. half the fluid speed.
E. one-quarter the fluid speed.
Answer: A

10. A12.5
An incompressible fluid with zero viscosity flows through a pipe of varying radius (shown in cross-section). Compared to the fluid at point P, the fluid at point Q has P Q
radius R
radius 2R
A. four times the fluid speed.
B. twice the fluid speed.
C. the same fluid speed.
D. half the fluid speed.
E. one-quarter the fluid speed.

11. Q-RT12.1
Rank the following objects in order from highest to lowest average density.
Answer: EDABC

12. A-RT12.1
Rank the following objects in order from highest to lowest average density.
Answer: EDABC

13. Q12.6
A nurse must apply thumb pressure p to administer an injection of a viscous liquid using a hypodermic needle with a small inside radius R. If instead the nurse uses a needle of the same length but with an even smaller inside radius R/2, how much thumb pressure will be required? (Assume that the volume flow rate is to be the same as with the first needle.)
A p
B. 2p
C. 4p
D. 8p
E. 16p
Answer: E

14. A12.6
A nurse must apply thumb pressure p to administer an injection of a viscous liquid using a hypodermic needle with a small inside radius R. If instead the nurse uses a needle of the same length but with an even smaller inside radius R/2, how much thumb pressure will be required? (Assume that the volume flow rate is to be the same as with the first needle.)
A p
B. 2p
C. 4p
D. 8p
E. 16p