to the impulse, which is the area under the force versus time graph. The
region under the graph from t = 0 to t = 0.4 sec is composed of a right
triangle (from t = 0 to t = 0.2 sec) plus a rectangle (from t = 0.2 sec to t = 0.4
sec), so the total area under the graph from t = 0 to t = 0.4 sec is (1/2)(0.2)
(100) + (0.4 − 0.2)(25) = 10 + 5 = 15 kg·m/sec.
- B Apart from sign, the magnification factor, m, is equal to i/o, where i is the
image distance from the lens and o is the object distance. In this case then,
we have m = i/o = (8 cm)/(20 cm) = 2/5.
- C The nth harmonic frequency is equal to n times the fundamental frequency,
f 1. Therefore
- C If both the source and detector travel in the same direction and at the same
speed, there will be no relative motion and hence no Doppler shift.
- C In a single medium, a wave travels a consistent speed. The frequency does
not change, so the wavelength must change (because the wave speed
changes).
- E Gamma rays and X-rays are very high-energy, short-wavelength radiations.
Ultraviolet light has a higher energy and shorter wavelength than visible
light. Within the visible spectrum, the colors are—in order of increasing
frequency—ROYGBV, so orange light (“O”) has a lower frequency—and
thus a longer wavelength—than blue light (“B”).
