The speed of a boat is often given in knots. If a speed of 5 knots were expressed in the SI system of units, the units would be:
a. m
c. m/s
b. s
d. kg/s
[Ques. 2] If the displacement of an object, x, is related to velocity, v, according to the relation x = Av, the constant, A, has the dimension of which of the following?
a. volume
c. time
b. length
d. area
[Ques. 3] Which expression is dimensionally consistent with an expression that would yield a value for time-1?(v is velocity, x is distance, and t is time)
a. v/x
c. x/t
b. v2/x
d. v2t
[Ques. 4] Which formula is dimensionally consistent with an expression yielding a value for velocity? (v is velocity, x is distance, and t is time)
a. v/t2
c. v2/t
b. vx2
d. v2t/x
[Ques. 5] When SI units are plugged into an equation, it is found that the units balance. Which of the following can we expect to be true for this equation?
a. The equation will be dimensionally correct.
b. The equation will be dimensionally correct except sometimes in cases when the right-hand side of the equation has more than one term.
c. The equation will not be dimensionally correct.
d. All constants of proportionality will be correct.
[Ques. 6] The information on a one-gallon paint can is that the coverage, when properly applied, is 270 ft2 . One gallon is 231 in3 . What is the average thickness of the paint in such an application?
a. 0.0036 in.
c. 0.043 in.
b. 0.0059 in.
d. 0.053 in.
[Ques. 7] The mass of the Sun is 2.0 1030 kg, and the mass of a hydrogen atom is 1.67 10-27 kg. If we assume that the Sun is mostly composed of hydrogen, how many atoms are there in the Sun?
a. 1.2 1056 atoms
c. 1.2 1057 atoms
b. 3.4 1056 atoms
d. 2.4 1057 atoms
[Ques. 8] When NASA was communicating with astronauts on the moon, the time from sending on the Earth to receiving on the moon was 1.28 s. Find the distance from Earth to the moon. (The speed of radio waves is 3.00 108 m/s.)
a. 240,000 km
c. 480,000 km
b. 384,000 km
d. 768,000 km
[Ques. 9] Water flows into a swimming pool at the rate of 12 gal/min. The pool is 16 ft wide, 32 ft long and 6.0 ft deep. How long does it take to fill? (1 U.S. gallon = 231 cubic inches)
a. 32 hours
c. 48 hours
b. 64 hours
d. 24 hours
[Ques. 10] A cement truck can pour 40 cubic yards of cement per hour. Express this in ft3/min.
a. 2/3 ft3/min
c. 6 ft3/min
b. 18 ft3/min
d. 2.0 ft3/min
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