The temperature of low pressure hydrogen is reduced from 100°C to 20°C. The rms speed of its molecules decreases by approximately:
Which, of the following temperature changes, would show the smallest change in entropy for a pan of water on a hot plate?
1. 20°C to 30°C
2. 30°C to 40°C
3. 40°C to 45°C
4. 80°C to 85°C
b. 1 and 2 are tied for smallest ΔS
The temperatures TC of the cold reservoirs and the temperatures TH of the hot reservoirs for four Carnot heat engines are
engine 1: TC = 400K and TH = 500K
engine 2: TC = 500K and TH = 600K
engine 3: TC = 400K and TH = 600K
engine 4: TC = 600K and TH = 800K
Rank these engines according to their efficiencies, least to greatest.
a. 1, 2, 3, 4
b. 1 and 2 tie, then 3 and 4 tie
c. 2, 1, 3, 4
d. 1, 2, 4, 3
e. 2, 1, 4, 3
An object hangs from a spring balance. The balance indicates 30N in air and 20N when the object is submerged in water. What does the balance indicate when the object is submersed in a liquid with a density that is half that of water?
Water flows through a cylindrical pipe of varying cross section. The velocity is 3.0m/s at a point where the pipe diameter is 1.0 cm. At a point where the pipe diameter is 3.0 cm, the velocity is: