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. 2] Three identical bar magnets, each 2 cm long, are placed in a straight line on a frictionless surface with their ends equally spaced with 2 cm between ends. They are constrained so they cannot rotate, but they can slide along the straight line. The left magnet has its north pole nearest the north pole of the middle magnet, and the right magnet has its south pole toward the middle magnet's south pole. Once they are in place and released from rest, which of the following best describes the motion of the magnets?
a. The end magnets will move away from the center magnet.
b. The magnets will not move since they are equally spaced.
c. The magnets will snap together.
d. None of the above would happen.
[Ques. 3] A mass of 4.5 kg, resting on a horizontal frictionless surface, is attached on the right to a horizontal spring with spring constant 29 N/m and on the left to a horizontal spring with spring constant 60 N/m. If this system is moved from equilibrium, what is the effective spring constant?
a. 31 N/m
b. 31 N/m
c. 89 N/m
d. 89 N/m
e. 16 N/m
[Ques. 4] Which of the following is not a hard magnetic material?
a. iron
b. cobalt
c. nickel
d. both b and c
[Ques. 5] A mass of 0.40 kg, attached to a spring with a spring constant of 40 N/m, is set into simple harmonic motion. What is the magnitude of the acceleration of the mass when at its maximum displacement of 0.25 m from the equilibrium position?
a. zero
b. 13 m/s2
c. 6.3 m/s2
d. 25 m/s2
e. 50 m/s2
[Ques. 6] A soft magnetic material has which property?
a. It cannot be magnetized.
b. It is easy to magnetize.
c. It is hard to magnetize.
d. It attracts slowly moving charges.
[Ques. 7] A tiny spring, with a spring constant of 1.30 N/m, will be stretched to what displacement by a 0.00500-N force?
a. 3.85 mm
b. 7.69 mm
c. 11.5 mm
d. 6.50 mm
e. 3.25 mm
[Ques. 8] Electrical charges and magnetic poles have many similarities, but one difference is:
a. opposite magnetic poles repel.
b. one magnetic pole cannot create magnetic poles in other materials.
c. a magnetic pole cannot be isolated.
d. magnetic poles do not produce magnetic fields.
[Ques. 9] Tripling 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. 0.33
b. 1.0
c. 3.0
d. 9.0
e. 0.11
[Ques. 10] An RL circuit has L = 0.45 H and R = 3.5 . It is connected to a battery with = 25 V at time t = 0 . Find the energy stored in the inductor when the current in the circuit is 0.25 A.
a. 14 mJ
b. 28 J
c. 110 J
d. 3.2 mJ
e. 800 J
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