# Physics

posted by .

(a) If the length of the Achilles tendon increases 0.55 cm when the force exerted on it by the muscle increases from 2200 N to 6000 N, what is the "spring constant" of the tendon?
N/m

(b) How much work is done by the muscle in stretching the tendon 0.55 cm as the force increases from 2200 N to 6000 N?
J

Could any one please explain this to me I don't know how to do it.Thank you.

• Physics -

Spring constant is defined as k = ∆F/∆x, change in force divided by change in spring length. ∆F = 6000-2200=3800N, and ∆x = 0.55 cm (0.0055 m), so k = 3800/0.0055 N/m =6.9•10^5 N/m

The energy stored in a deflected spring is
kΔx²/2 = 6.9•10^5•3•10^-5/2 =10.35 J ; this must equal the work done in changing the spring length. So for the muscle, W = 10.35 J

## Similar Questions

1. ### College Physics

As part of an exercise program, a 75 kg person does toe raises in which he raises his entire body weight on the ball of one foot. The Achilles tendon pulls straight upward on the heel bone of his foot. This tendon is 25 cm long and …
2. ### Physics

The Achilles tendon, which connects the calf muscles to the heel, is the thickest and strongest tendon in the body. In extreme activities, such as sprinting, it can be subjected to forces as high as 13.0 times a person's weight. According …
3. ### Physics

The Achilles tendon, which connects the calf muscles to the heel, is the thickest and strongest tendon in the body. In extreme activities, such as sprinting, it can be subjected to forces as high as 13.0 times a person's weight. According …
4. ### AP Physics - Equilibrium

The Achilles tendon is attached to the rear of the foot as shown in the figure below. When a person elevates himself just barely off the floor on the ball of one foot, estimate the tension Ft in the Achilles tendon (pulling upward) …
5. ### Physics

If a 60 kg person stands on a low wall with her full weight on the ball of one foot and the heel free to move, the stretch of the Achilles tendon will cause her center of gravity to lower by about 2.5 mm. What is the spring constant …
6. ### physics

When you stand on your tiptoes, your feet pivot about your ankle. As shown in the figure, the forces on your foot are an upward force on your toes from the floor, a downward force on your ankle from the lower leg bone, and an upward …
7. ### Physics

The Achilles tendon, which connects the calf muscles to the heel, is the thickest and strongest tendon in the body. In extreme activities, such as sprinting, it can be subjected to forces as high as 13 times a person’s weight. According …
8. ### Physics

The Achilles tendon is attached to the rear of the foot as shown in (Figure 1) . A person elevates himself just barely off the floor on the "ball of one foot." Assume the person has a mass of 65kg and D is twice as long as d. Find …
9. ### Physics

Human feet and legs store elastic energy when walking or running. They are not nearly as efficient at doing so as kangaroo legs, but the effect is significant nonetheless. If not for the storage of elastic energy, a 70.0-kg man running …
10. ### Physics

A 83.2-kg man stands on his toes by exerting an upward force through the Achilles tendon, as in the figure below. What is the force in the Achilles tendon if he stands on one foot?

More Similar Questions