A wheel rotating about a fixed axis has a constant angular acceleration of 4.0 rad/s2. In a 4.0-s interval the wheel turns through an angle of 80 radians. Assuming the wheel started from rest, how long had it been in motion at the start of the 4.0-s interval?
A. 2.5 s
B. 4.0 s
C. 3.5 s
D. 3.0 s
E. 4.5 s
Answer: D
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Simple Harmonic Motion: The figure shows a graph of the velocity v as a function of time t for a system undergoing simple harmonic motion. Which one of the following graphs represents the acceleration of this system as a function of time?
A. graph a B. graph b C. graph c D. graph d
In order to produce a sustained interference pattern by light waves from multiple sources, which of the following conditions must be met?
a. Sources are monochromatic. c. Both choices a and b are valid. b. Sources are coherent. d. None of these are valid.
Astronauts approaching a black hole would observe that _____
a. time appears to slows down for them b. time appears to speed up for external observers c. they become squashed flat - their heads and feet are pushed together by gravitational tides d. they become stretched thin - their heads and feet are pulled apart by gravitational tides e. nothing appears to change
Two concentric circular wire loops in the same plane each carry a current. The larger loop as a current of 8.46 A circulating clockwise and has a radius of 6.20 cm. The smaller loop has a radius of 4.42 cm. What is the magnitude and direction of the current in the smaller loop if the total magnetic field at the center of the system is zero?
A. 6.03 A CCW B. 6.03 A CW C. 12.8 A CCW D. 12.8 A CW