Students attach a thin strip of metal to a table so that the strip is horizontal in relation to the ground. A section of the strip hangs off the edge of the table. A mass is secured to the end of the hanging section of the strip and is then displaced so that the mass-strip system oscillates .Students make various measurements of the net force F exerted on the mass as a result of the force due to gravity and the normal force from the strip, the vertical position y of the mass above and below its equilibrium position y, and the period of oscillation T when the mass is displaced by different amplitudes A. Which of the following explanations is correct about the evidence required to conclude that the mass undergoes simple harmonic motion? A. The period T of oscillation depends on the amplitude A of the mass, because the students can directly change this value during the experiment.
B. The net force F exerted on the mass must be directly proportional to the vertical position y, because the net force exerted on the mass is the restoring force.
C. The mass’s acceleration is proportional to the square of the vertical position y because the elastic potential energy of the mass-strip system can be modeled by the equation for spring potential energy.
D. The motion of the mass repeats after a specific time interval, because total mechanical energy is considered to be conserved in simple harmonic motion.