While unrealistic, we will examine the forces on a leg when one falls from a height...

While unrealistic, we will examine the forces on a leg when one falls from a height by approximating the leg as a uniform cylinder of bone with a diameter of 2.3 cm and ignoring any shear forces. Human bone can be compressed with approximately 1.7 × 108 N/m2 before breaking. A man with a mass of 80 kg falls from a height of 4 m. Assume his acceleration once he hits the ground is constant. For these calculations, g = 10 m/s2.

Part A

What is his speed just before he hits the ground?

Part B

With how much force can the "leg" be compressed before breaking?

Part C

If he lands "stiff legged" and his shoes only compress 1 cm, what is the magnitude of the average force he experiences as he slows to a rest?

Part D

If he bends his legs as he lands, he can increase the distance over which he slows down to 50 cm. What would be the average force he experiences in this scenario?

Part E

Dyne is also a unit of force and 1 Dyn = 10−5 N. What is the maximum a bone can be compressed in Dyn/cm2?

Solutions

Expert Solution

genius_generous answered 1 month ago

Next > < Previous

Related Solutions

Very large forces are produced in joints when a person jumps from some height to the...

Very large forces are produced in joints when a person jumps from some height to the ground. a) Calculate the force exerted if a 96kg person jumps from a 0.6m high ledge and lands stiffly, compressing joint material 3.4cm as a result. (Be certain to include the weight of the person.) b) In practice the knees bend almost involuntarily to help extend the distance over which you stop. Calculate the force exerted if the stopping distance is 0.3m. c) Determine...

An object falls from a height h from rest. If it travels a fraction of the...

An object falls from a height h from rest. If it travels a fraction of the total height of 0.5833 in the last 1.00 s, find the time of its fall. Find the height of its fall

Suppose an object falls from a great height on a planet where the constant of the...

Suppose an object falls from a great height on a planet where the constant of the acceleration of gravity is g = 7.84. Assume that the resistance of the atmosphere is proportional to the square of the velocity of the object with constant of proportionality k = 0.25. Establish and solve an Initial Value Problem to express the velocity of the object as a function of time. Find the terminal velocity of the object. Graph this function. Then express the...

Question: One criticism often heard about economics is that the models we use are unrealistic: in...

Question: One criticism often heard about economics is that the models we use are unrealistic: in seeking t... One criticism often heard about economics is that the models we use are unrealistic: in seeking to keep the scope of our work more manageable by making certain assumptions or ignoring certain details, we may oversimplify the situation. Write one paragraph on whether you agree or disagree with this criticism. Why do we use models at all, and how should we balance...

If a ball falls in vacuum from a certain height describe the total energy, the kinetic...

If a ball falls in vacuum from a certain height describe the total energy, the kinetic energy, and the potential energy during the fall. Describe the energy values at the initial point (highest point), at an intermediate point during the fall, and at the final point (ground level). Make sure to mention how the free fall in vacuum is different from a real life fall.

You are covering a soccer game when while heading a ball an athlete falls grabbing the...

You are covering a soccer game when while heading a ball an athlete falls grabbing the back of their lower leg. You are concerned they may have strained their calf. What would the athlete complain of (symptoms) and what would you observe (signs) if they had suffered a 2nd degree strain? What are some predisposing factors that may have put the athlete at risk for this injury? For a 2nd degree strain, what positive tests would you expect to find...

A 200 gram of ice block falls from a height of 80 meters onto a bucket...

A 200 gram of ice block falls from a height of 80 meters onto a bucket of 1 kg water in a copper bucket of mass 100 grams. The initial temperature of the ice is 0 and the bucket and water is 20 C. Assume that 60% of the potential energy of the ice block goes into heat!!!! What is the final temperature of the ice, water and bucket mixture?? If not all the ice melts, then what is the...

Consider a 4-mg raindrop that falls from a cloud at a height of 2 km. Part...

Consider a 4-mg raindrop that falls from a cloud at a height of 2 km. Part a) If we neglect air resistance, what would be the speed of the raindrop when it reaches the ground? Assume that the falling raindrop maintains its shape so that no energy is lost to the deformation of the droplet. ________ m/s Part b) When the raindrop reaches the ground, it won't kill you or even bruise you because its terminal velocity is just 10...

Len is a 59 kg pole vaulter and he falls from a peak height of 5.0...

Len is a 59 kg pole vaulter and he falls from a peak height of 5.0 meters after pole-vaulting over the crossbar set at that height. He lands on a thick mat and when he first makes contact with the mat, his centre of gravity is only 0.91 meters high. During Len's impact with the mat, it undergoes a maximum compression when his vertical velocity reaches 0 m/s and his centre of gravity is only 0.4 meters high. What is...

Water falls without splashing at a rate of 0.400 L/s from a height of 3.60 m...

Water falls without splashing at a rate of 0.400 L/s from a height of 3.60 m into a 0.530-kg bucket on a scale. If the bucket is originally empty, what does the scale read 3.40 s after water starts to accumulate in it?

Subjects