A mass tied to the end of a 1.0 m-long string is swinging back and forth From its lowest point, the mass moves 4 cm to the right, swings back through its lowest point to stop 4 cm to the left of its lowest point, then swings back to where it started. One complete swing takes about 2 s. If the amplitude of motion is doubled, so the mass swings 8 cm to one side and then the other, the period of the motion will be a. 2s b. 4 s c. 6s d. 8s