Bats can detect small objects such as insects that are of a size on the order of a wavelength. If bats emit a chirp at a frequency of 60 kHz and the speed of soundwaves in air is 330 m/s, what is the smallest size insect they can detect?
a. 1.5 mm
b. 3.5 mm
c. 5.5 mm
d. 7.5 mm
e. 9.8 mm
c
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?Suppose a particle is moving along a straight line with a speed v for a time t, then stops for a time t, and then resumes moving along the original direction with speed v for time t. What has been the average speed of the particle for the total time period 3t?
A) v
B) 
C) 1.5v
D) 
Imagine for a moment that despite all the evidence, Earth actually is not rotating and orbiting the Sun. Which of these hypothetical observations (none of them are real) would be inconsistent with our Sun-centered view of the solar system?
A) We find that we are unable to measure any parallax for a distant galaxy. B) We discover an Earth-sized planet orbiting the Sun beyond the orbit of Pluto. C) We discover that the universe is actually contracting, not expanding. D) We discover a small planet beyond Saturn that rises in the west and sets in the east each day.
A solid sphere of mass 2.50 kg and radius 0.120 m is at rest at the top of a ramp inclined 15.0°. It rolls to the bottom without slipping. The upper end of the ramp is 1.20 m higher than the lower end. Find the sphere's total kinetic energy when it reaches the bottom
a. 70.0 J b. 47.9 J c. 29.4 J d. 8.80 J
Charge of uniform density 12 nC/m is distributed along the x axis from x = 2.0 m to x = 5.0 m. What is the electric potential (relative to zero at infinity) at the origin (x = 0)?
a. 91 V b. 99 V c. 82 V d. 74 V e. 140 V