18.1. The Big Idea http://www.ck12.org
spherical capsule used for ocean descent – a cable is attached to the top, and this cable is attached to a winch
on your boat on the surface.
a. Name and sketch your bathysphere.
b. What is the radius of your bathysphere in meters? (You choose – estimate from your picture.)
c. What is the volume of your bathysphere inm^3?
d. What is the pressure acting on your bathysphere at a depth of 11,000 m? The density of sea water is
1027 kg/m^3.
e. If you had a circular porthole of radius 0.10 m(10 cm)on your bathysphere, what would the inward force
on the porthole be?
f. If the density of your bathysphere is 1400 kg/m^3 , what is the magnitude of the buoyant force acting on
it when it is at the deepest point in the trench?
g. In order to stop at this depth, what must the tension in the cable be? (Draw an FBD!)Answers to Selected Problems
- 84
- 4 × 105 kg
- a. 90% of the berg is underwater b. 57%
- b. 5. 06 × 10 −^4 N c. 7.05 m/s^2
- 4.14 m/s
- 40 coins
- b. upward c. 4.5 m/s^2 d. Cooler air outside, so more initial buoyant force e. Thin air at high altitudes weighs
almost nothing, so little weight displaced. - a. At a depth of 10 cm, the buoyant force is 2.9 N d. The bottom of the cup is 3 cm in radius
- a. 83,000 Pa b. 104 N c. 110 N
- a. 248 kPa b. 591 kPa c. 1081 kPa
11..
12.. 0081 - a. 12500 J/m^3 b. 184 kPa c. 1.16 kW d. 2.56 kW e. 11.8 A f. $12. 60
- a. 611 kPa b. 6 atm
- b. 500,000 N
- a. 27 m/s^2 ,( 2 .7 g)upward b. 1600 N c. 2200 N
- a. 10 N b. 10.5 N c. 11 N d. 11 N
- a. “The Thunder Road” b. 2.0 m (note: here and below, you may choose differently) c. 33.5 m^3 e. 3.5 million N
f. 111 MPa