A radar pulse sent out to an airplane at a distance of 20.0 km will return as an echo to the source in what time interval? (c = 3.00 × 10^8 m/s)
a. 33.3 × 10^-6 s
c. 66.7 × 10^-6 s
b. 133 × 10^-6 s
d. 0.0333 × 10^-6 s
B
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If the theory that novae occur in close binary systems is correct, then recurrent novae should
a. produce synchrotron radiation. b. occur in regions of star formation. c. not occur in old star clusters. d. all be visual binaries. e. repeat after some interval.
Dark energy is made of
A) weak force fields that were created during the big bang. B) fast moving "gluons" that were created during the big bang. C) an unknown material that has never been directly observed in laboratories. D) slow-moving "magnetons" that were created during the big bang. E) invisible electromagnetic fields.
To predict the approximate energy release of either a fission or a fusion reaction, explain how a physicist uses a table of nuclear masses and the equation E = mImage
A) find the change in mass and divided by the speed of light squared B) find the change in mass and multiply by the speed of light squared C) find the change in mass, square it, and multiply by the speed of light D) take the square root of the change in mass and multiply by the speed of light
A skydiver jumps out of a hovering helicopter. A few seconds later, another skydiver jumps out, so they both fall along the same vertical line relative to the helicopter. Both skydivers fall with the same acceleration. (Assume g is constant.) The difference in their velocities
1.increases. 2.decreases. 3.stays the same.