we saw that a runner’s Achilles tendon will stretch like a spring and then rebound, storing and returning energy during a step. We can model this as the simple harmonic motion of a massspring system. When the foot rolls forward, the tendon spring begins to stretch as the weight moves to the ball of the foot, transforming kinetic energy into elastic potential energy. This is the first phase of an oscillation. The spring then rebounds, converting potential energy to kinetic energy as the foot lifts off the ground. The oscillation is fast: Sprinters running a short race keep each foot in contact with the ground for about 0.10 second, and some of that time corresponds to the heel strike and subsequent rolling forward of the foot. Given what you have calculated for the period of the full oscillation in this model, what is the landing-to-liftoff time for the stretch and rebound of the sprinter’s foot?A. 0.050 s B. 0.10 sC. 0.15 s D. 0.20 s
Simple harmonic motion
Simple harmonic motion is a type of periodic motion in which an object undergoes oscillatory motion. The restoring force exerted by the object exhibiting SHM is proportional to the displacement from the equilibrium position. The force is directed towards the mean position. We see many examples of SHM around us, common ones are the motion of a pendulum, spring and vibration of strings in musical instruments, and so on.
Simple Pendulum
A simple pendulum comprises a heavy mass (called bob) attached to one end of the weightless and flexible string.
Oscillation
In Physics, oscillation means a repetitive motion that happens in a variation with respect to time. There is usually a central value, where the object would be at rest. Additionally, there are two or more positions between which the repetitive motion takes place. In mathematics, oscillations can also be described as vibrations. The most common examples of oscillation that is seen in daily lives include the alternating current (AC) or the motion of a moving pendulum.
we saw that a runner’s Achilles tendon will stretch like a spring and then rebound, storing and returning energy during a step. We can model this as the
Given what you have calculated for the period of the full oscillation in this model, what is the landing-to-liftoff time for the stretch and rebound of the sprinter’s foot?
A. 0.050 s B. 0.10 s
C. 0.15 s D. 0.20 s
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