Two parallel wires are separated by 0.25 m. Wire A carries 4.1 A and Wire B carries 10 A, both currents in the same direction. The magnetic permeability in empty space 0 = 4p 10-7 Tm/A. The magnitude of the force on 1.4 m of Wire A is:
a. 2.6 105 N.
c. less than 1.0 105 N.
b. 4.6 105 N.
d. 3.2 105 N.
[Ques. 2] Suppose there is an object for which F = +kx. What will happen if the object is moved away from equilibrium (x = 0) and released?
a. It will return to the equilibrium position.
b. It will move further away with constant velocity.
c. It will move further away with constant acceleration.
d. It will move further away with increasing acceleration.
[Ques. 3] Two parallel wires are separated by 0.25 m. Wire A carries 5.0 A and Wire B carries 10 A, both currents in the same direction. The force on 0.80 m of Wire A is:
a. away from Wire B.
c. half that on 0.80 m of wire B.
b. toward Wire B.
d. one-fourth that on 0.80 m of wire B.
[Ques. 4] A mass of 4.0 kg, resting on a horizontal, frictionless surface, is attached on the right to a horizontal spring with spring constant 30 N/m and on the left to a horizontal spring with spring constant 50 N/m. If this system is moved from equilibrium, what is the effective spring constant?
a. 16 N/m
c. 20 N/m
b. 80 N/m
d. -20 N/m
[Ques. 5] Consider two long, straight parallel wires, each carrying a current I. If the currents are flowing in the same direction:
a. the two wires will attract each other.
b. the two wires will repel each other.
c. neither wire will exert a force on the other.
d. the two wires will exert a torque on each other.
[Ques. 6] A mass of 0.40 kg, attached to a spring with a spring constant of 80 N/m, is set into simple harmonic motion. What is the magnitude of the acceleration of the mass when at its maximum displacement of 0.050 m from the equilibrium position?
a. zero
c. 10 m/s2
b. 5 m/s2
d. 20 m/s2
[Ques. 7] Two parallel conductors each of 0.50-m length, separated by 5.0 10-3 m and carrying 3.0 A in the same direction, will experience what type and magnitude of mutual force? (magnetic permeability in empty space 0 = 4p 10-7 Tm/A)
a. attractive, 1.8 10-4 N
c. repulsive, 0.60 10-4 N
b. repulsive, 1.8 10-4 N
d. attractive, 0.06 10-4 N
[Ques. 8] A tiny spring, with a spring constant of 1.20 N/m, will be stretched to what displacement by a 0.0060-N force?
a. 4.2 mm
c. 6.0 mm
b. 5.0 mm
d. 9.4 mm
[Ques. 9] Two parallel conductors are carrying currents in the opposite direction. The currents are non-zero and not necessarily equal. The magnitude of the magnetic field midway between them is 40 mT. If one of the currents then has its direction reversed, what is the resulting magnitude of the magnetic field midway between them?
a. a value greater than 40 mT
c. 40 mT
b. a value less than 40 mT
d. It could be any value.
[Ques. 10] Doubling the displacement from equilibrium of an object in simple harmonic motion will bring about a change in the magnitude of the object's acceleration by what factor?
a. 4.0
c. 1.0
b. 2.0
d. 0.5
Quick Reply
