An LR circuit contains an ideal 60-V battery, a 51-H inductor having no resistance, a 21-? resistor, and a switch S, all in series
Initially, the switch is open and has been open for a very long time. At time t = 0 s, the switch is suddenly closed. When the voltage across the resistor is equal to the voltage across the inductor, what is the current in the circuit?
A) 1.4 A
B) 0.57 A
C) 1.1 A
D) 0.86 A
E) 1.7 A
Answer: A
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A machinist needs to remove a tight fitting pin of material A from a hole in a block made of material B. The machinist heats both the pin and the block to the same high temperature and removes the pin easily
What statement relates the coefficient of thermal expansion of material A to that of material B? A) Material B has a greater coefficient of expansion than does material A. B) The situation is not possible because heating block B will shrink the hole in the material as the material expands with increasing temperature. C) Material B has the same coefficient of expansion as does material A. D) Material A has a greater coefficient of expansion than does material B.
A 600-kg car is going around a curve with a radius of 120 m that is banked at an angle of 25.0° with a speed of 30.0 m/s. The coefficient of static friction between the car and the road is 0.300. What is the force exerted by friction on the car?
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A flat rectangular coil with dimensions of 8.0 cm × 10 cm is dropped from a zero magnetic field position into a 1.4-T magnetic field in 0.10 s
The coil has 60 turns and is perpendicular to the magnetic field. What is the average induced emf in the coil as a result of this action? A) 8.6 V B) 2.4 V C) 6.7 V D) 3.6 V E) 0 V
A person pushes on a doorknob with a force of 5.00 N perpendicular to the surface of the door. The doorknob is located 0.800 m from axis of the hinges of the door. The door begins to rotate with an angular acceleration of 2.00 rad/s2
What is the moment of inertia of the door about the hinges? A) 2.00 kg?m2 B) 1.00 kg?m2 C) 12.5 kg?m2 D) 8.00 kg?m2 E) 6.40 kg?m2