A spring has a spring constant of 50 N/m. If you stretch the spring 0.2 m past'
its natural length, what force does the spring apply?

i think the answer is a, hope this is right, that would be my best guess.

close lines strong magnet less close weaker

the motion of a pendulum is a classic example of mechanical energy conservation. a pendulum consists of a mass (known as a bob ) attached by a string to a pivot point. as the pendulum moves it sweeps out a circular arc, moving back and forth in a periodic fashion.