In a certain one-lane road there are no entrances or exits. As the road passes through open country and populated areas, the speed limit changes. Assume that cars travel at the posted speed limit
In the open road, where the speed limit is 55 mph, the cars are spaced so there are 51 cars per mile. If the flow of cars is steady, how many cars per mile are there in a stretch of road where the speed limit is 40 mph? A) 56 cars/mile
B) 60 cars/mile
C) 66 cars/mile
D) 70 cars/mile
E) 76 cars/mile
D
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Of the main types of radiation emitted from naturally radioactive isotopes, which of the following is the most penetrating?
a. alpha b. beta (electron) c. gamma d. beta (positron)
Wien's Law: As the temperature of a blackbody increases, what happens to the peak wavelength of the light it radiates?
A. It gets longer. B. It gets shorter. C. The wavelength is not affected by the temperature of the object.
Simple harmonic oscillations can be modeled by the projection of circular motion at constant angular velocity onto a diameter of the circle. When this is done, the analog along the diameter of the acceleration of the particle executing simple harmonic motion is
A. the displacement from the center of the diameter of the projection of the position of the particle on the circle. B. the projection along the diameter of the velocity of the particle on the circle. C. the projection along the diameter of tangential acceleration of the particle on the circle. D. the projection along the diameter of centripetal acceleration of the particle on the circle. E. meaningful only when the particle moving in the circle also has a non-zero tangential acceleration.
You intend to move a rectangular loop of wire into a region of uniform magnetic field at a given speed so as to induce an emf in the loop. The plane of the loop must remain perpendicular to the magnetic field lines. In which orientation should you hold the loop while you move it into the region with the magnetic field to generate the largest emf?
1.with the long dimension of the loop parallel to the velocity vector 2.with the short dimension of the loop parallel to the velocity vector 3.Either way because the emf is the same regardless of orientation.