17.1. Buoyancy http://www.ck12.org
- A glass of water with weight 10 N is sitting on a scale, which reads 10 N. An antique coin with weight 1 N is
placed in the water. At first, the coin accelerates as it falls with an acceleration ofg/2. About half-way down
the glass, the coin reaches terminal velocity and continues at constant speed. Eventually, the coin rests on the
bottom of the glass. What was the scale reading when:
a. The coin had not yet been released into the water?
b. The coin was first accelerating?
c. The coin reached terminal velocity?
d. The coin came to rest on the bottom?
Answers to Selected Problems
- 84
- 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
- b. 500,000 N
- a. 10 N b. 10.5 N c. 11 N d. 11 N