The Framingham Study and the two lung cancer studies are examples of retrospective cohort studies that followed large numbers of people over extended periods of time.
a. true
b. false
b. false
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Constant Angular Acceleration: A machinist turns on the power to a grinding wheel at time t = 0 s. The wheel accelerates uniformly from rest for 10 s and reaches the operating angular speed of 38 rad/s. The wheel is run at that angular speed for 30 s and then power is shut off. The wheel slows down uniformly at 2.1 rad/s2 until the wheel stops. In this situation, what is the angular acceleration of the wheel between t = 0 s and t = 10 s?
A. 3.8 rad/s2 B. 4.6 rad/s2 C. 5.3 rad/s2 D. 6.1 rad/s2 E. 6.8 rad/s2
Which of the following best explains the hypothesized phenomenon of black hole evaporation?
A) Particles (or anti-particles) are created by a quantum mechanical effect near, but outside, the event horizon of the black hole. The law of conservation of energy maintains that the black hole must lose energy to "pay" for the creation of this mass. B) Particles (or anti-particles) are occasionally ejected from within the event horizon, causing the black hole to lose mass. C) Virtual particles created near the black hole are constantly annihilating each other, causing a high temperature even if the black hole has no accretion disk. This high temperature provides escape velocity for the virtual particles, causing the entire "cloud" of virtual particles to expand away into space. D) Black hole evaporation is a virtual process, meaning that it has been theorized by astrophysicists, but doesn't really occur.
From the center outward, the correct order of the zones of Earth is
A. liquid core, solid core, crust, mantle, atmosphere. B. liquid core, solid core, mantle, crust, atmosphere. C. solid core, liquid core, mantle, crust, atmosphere. D. solid core, mantle, liquid core, crust, atmosphere.
Impedance is the total, or effective, opposition to current that takes into account both resistances and reactances
Indicate whether the statement is true or false