21-cm radiation is a result of an electron in hydrogen flipping its spin direction
Indicate whether the statement is true or false
TRUE
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A 1200-kg pick-up truck traveling south at 15 m/s suddenly collides with a 750-kg car that is traveling east. The two vehicles stick together and slide along the road after colliding
A highway patrol officer investigating the accident determines that the final position of the wreckage after the collision is 25 m, at an angle of 50° south of east, from the point of impact. She also determines that the coefficient of kinetic friction between the tires and the road at that location was 0.40. What was the speed of the car just before the collision? A) 20 m/s B) 4.8 m/s C) 14 m/s D) 23 m/s E) 17 m/s
Assuming equal rates of acceleration in both cases, how much longer would it take a car to stop if braking from 56 mi/h than from 28 mi/h?
A) 8 times as long B) 4 times as long C) 2 times as long D) 1.4 times as long E) the same in both cases
Suppose there is an object for which F = +kx. What will happen if the object is moved away from equilibrium (x = 0) and released?
a. It will return to the equilibrium position. b. It will move further away with constant velocity. c. It will move further away with constant acceleration. d. It will move further away with increasing acceleration.
The force of gravity is the only one of the four forces felt on very large size scales. Which of the following best explains why the other forces don't play a major role on large scales?
A) The other three forces are all very short in range, and cannot be felt over large distances. B) The strong and weak forces act only on very small scales, and large objects tend to be electrically neutral and therefore don't feel an electromagnetic force. C) Gravity is by far the strongest force, so it simply dominates on large size scales. D) Effects of the strong and weak forces tend to cancel out effects of the electromagnetic force on large scales.