What is an advantage of using chlorine gas to disinfect drinking water supplies?
A) It provides residual protection against pathogens.
B) It gives the water a fresh taste.
C) Residual chlorine in water helps to whiten teeth.
D) Excess chlorine is absorbed in our bodies as a mineral supplement.
Answer: A
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Impulse: A batter hits a foul ball. The 0.14-kg baseball that was approaching him at 40 m/s leaves the bat at 30 m/s in a direction perpendicular to the line between the batter and the pitcher. What is the magnitude of the impulse delivered to the baseball?
A. 9.8 N ? s B. 1.4 N ? s C. 3.5 N ? s D. 5.6 N ? s E. 7.0 N ? s
Cygnus X-1 and LMC X-3 are black holes if the masses of the unseen companions are
a. less than 5 solar masses. b. more than 5 solar masses. c. between 0.4 and 1.4 solar masses. d. less than 0.4 solar masses e. not larger than the masses of the stars that we can see.
A 0.50-kg mass attached to the end of a string swings in a vertical circle (radius = 2.0 m). When the string is horizontal, the speed of the mass is 8.0 m/s. What is the magnitude of the force of the string on the mass at this position?
a. 16 N b. 17 N c. 21 N d. 11 N e. 25 N
Consider the two systems below, labeled A and B
A B
Which gas has the higher pressure?