a$)$ How can a spring, a ball dropped to the ground, and a bridge can exhibit harmonic motion?b$)$ If a bridge swings or becomes wobbly during high winds, what could be done to correct this?c$)$ Which component of gravitational force contributes to the arc motion of a simple pendulum?d$)$ If the mass of a simple pendulum bob is doubled, how does this affect the period of motion?e$)$ Does the period of the pendulum change if it is elevated? What about accelerating upward?