Parallel Wires: A ring with a clockwise current (as viewed from above the ring) is situated with its center directly above another ring, which has a counter-clockwise current, as shown in the figure. In what direction is the net magnetic force exerted on the top ring due to the bottom ring?
A. upward
B. downward
C. to the left
D. to the right
E. The net force is zero.
Answer: A
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Our galaxy is suspected to be surrounded by a galactic halo or corona because the disk of the galaxy
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The output voltage of an AC generator is of the form V = V0 sin(2?ft). A typical frequency in household circuits is 60 Hz. Using radians for angular measure in this equation, what is the factor 2?f in radians per second for this frequency?
a. 2? b. 120 c. 377 d. 60
Car A rear ends Car B, which has twice the mass of A, on an icy road at a speed low enough so that the collision is essentially elastic. Car B is stopped at a light when it is struck. Car A has mass m and speed v before the collision. After the collision
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A 3.00 g lead bullet is traveling at a speed of 300 m/s when it embeds in a wood post. If we assume that half of the resultant heat energy generated remains with the bullet, what is the increase in temperature of the embedded bullet? (specific heat of lead = 0.0305 kcal/kg• °C, 1 kcal = 4186 J)
a. 113°C c. 176°C b. 137°C d. 259°C