1answer.
Ask question
Login Signup
Ask question
All categories
  • English
  • Mathematics
  • Social Studies
  • Business
  • History
  • Health
  • Geography
  • Biology
  • Physics
  • Chemistry
  • Computers and Technology
  • Arts
  • World Languages
  • Spanish
  • French
  • German
  • Advanced Placement (AP)
  • SAT
  • Medicine
  • Law
  • Engineering
mel-nik [20]
2 years ago
8

The maximum energy a bone can absorb without breaking is surprisingly small. For a healthy human of mass 60 kg60 kg, experimenta

l data show that the leg bones can absorb about 200 J.
Required:
a. From what maximum height could a person jump and land rigidly upright on both feet without breaking his legs? Assume that all energy is absorbed in the leg bones in a rigid landing.
b. People jump from much greater heights than this; explain how this is possible.
Physics
1 answer:
netineya [11]2 years ago
5 0

Answer:

<em>the maximum height a man can jump from and land rigidly upright on both feet without breaking his legs is 0.34 m</em>

<em></em>

Explanation:

Mass of a healthy man = 60 kg

energy the bone can take without breaking = 200 J

If a healthy man jumps from a height 'h', he falls with an energy equal to the potential energy due to his initial height above the ground.

initial potential energy of the healthy man = mgh

where m = mass of the man

g = acceleration due to gravity = 9.81 m/s^2

h = the height above ground

==> PE = 60 x 9.81 x h = 588.6h

If we assume that all energy is absorbed in the leg bones in a rigid landing, then we can safely say that this calculated PE for a healthy man is equal to the energy his bone can absorb in the jump without breaking.

equating, we have

200 = 588.6h

<em>the maximum height a man can jump from without breaking his legs = 200/588.6 = 0.34 m</em>

When people jump from a height, the sudden deceleration to zero can impact a big force on the leg bones, shattering them. If the time spent in decelerating to zero is increased, the overall force on the leg bones is reduced greatly.

<em>Bending the knees gradually on landing from a jump from a height, and then rolling increases the time spent decelerating, and reduces the impact force on the legs due to the landing</em>. If you observe carefully you will see that this is what professional stunts men and acrobats do when they jump from a height.

You might be interested in
A 150-newton force, applied to a wooden crate at an angle of 30° above the horizontal, causesthe crate to travel at constant vel
omeli [17]

Answer:

Explanation:

A component of 150 N in vertical direction will reduce the magnitude of reaction force.

reaction force exerted by the floor

= mg - 150 sin 30

where m is mass of the crate .

the magnitude of the horizontal component of the 150-newton force

150 cos30

= 130 N

This force tries to pull the crate in forward direction with acceleration but it has no acceleration . It is so because frictional force of equal magnitude acts on it in opposite direction which makes the net force acting on it equal to zero.

Hence frictional force is equal to 150 cos 30.

= 130 N .

3 0
3 years ago
True or false? Once the sun explodes, the whole solar system will go with it.
liberstina [14]
True. That is how powerful the sun is. But it will explode in only about 5 billion years.
6 0
3 years ago
Pascal in term fundamental unit is? ​
Aleksandr-060686 [28]

Answer: SI unit of pressure

Explanation: The pascal (pronounced pass-KAL and abbreviated Pa) is the unit of pressure or stress in the International System of Units (SI). Reduced to base units in SI, one pascal is one kilogram per meter per second squared; that is, 1 Pa = 1 kg · m-1 · s-2.

Hope this helps! Have a fantastic rest of ur day, luv!

8 0
3 years ago
A small object of mass 3.82 g and charge -16.5 µC is suspended motionless above the ground when immersed in a uniform electric f
horrorfan [7]

Answer:

2271.16N/C  upward

Explanation:

The diagram well illustrate all the forces acting on the mass. The weight is acting downward and the force is acting upward in other to balance the weight.since the question says it is motionless, then indeed the forces are balanced.

First we determine the downward weight using

W=mg\\g=9.81m/s^{2}

Hence for a mass of 3.82g 0r 0.00382kg we have the weight to be

W=0.00382kg*9.81m/s^{2}

W=0.0375N

To calculate the electric field,

E=f/q\\E=0.0375/16.5*10^{-6} \\E=2271.16N/C

Since the charge on the mass is negative, in order to generate upward force, there must be a like charge below it that is  repelling it, Hebce we can conclude that the electric field lines are upward.

Hence the magnitude of the electric force is 2271.16N/C and the direction is upward

4 0
3 years ago
Suppose the gas resulting from the sublimation of 1.00 g carbon dioxide is collected over water at 25.0◦c into a 1.00 l containe
AlexFokin [52]

Answer:

0.56 atm

Explanation:

First of all, we need to find the number of moles of the gas.

We know that

m = 1.00 g is the mass of the gas

Mm=44.0 g/mol is the molar mass of the carbon dioxide

So, the number of moles of the gas is

n=\frac{m}{M_m}=\frac{1.00 g}{44.0 g/mol}=0.023 mol

Now we can find the pressure of the gas by using the ideal gas equation:

pV=nRT

where

p is the pressure

V=1.00 L = 0.001 m^3 is the volume

n = 0.023 mol is the number of moles

R=8.314 J/mol K is the gas constant

T=25.0^{\circ}+273=298 K is the temperature of the gas

Solving the equation for p, we find

p=\frac{nRT}{V}=\frac{(0.023 mol)(8.314 J/mol K)(298 K)}{0.001 m^3}=5.7 \cdot 10^4 Pa

And since we have

1 atm = 1.01\cdot 10^5 Pa

the pressure in atmospheres is

p=\frac{5.7\cdot 10^4 Pa}{1.01\cdot 10^5 Pa/atm}=0.56 atm

5 0
3 years ago
Other questions:
  • A stubborn 130 kg pig sits down and refuses to move. to drag the pig to the barn, the exasperated farmer ties a rope around the
    6·1 answer
  • The speed of light in water is 2.25 x 108 m/s. What is true about the index of refraction of water? A. It is less than 1. B. It
    11·2 answers
  • What happens to lava as its temperature increases?
    15·1 answer
  • The atomic number of an element is determined by the number of A. electrons. B. protons. C. protons and neutrons. D. neutrons.
    13·1 answer
  • What is one advantage the Hyperloop would have over other types of transportation?
    14·2 answers
  • If an object is 413 Kg in mass and 640 M3. What is the density? Will It Float?
    15·1 answer
  • How did Albert Einstein come up with 3 = mc square pls help
    9·1 answer
  • Explain why white light splits up into the different colours when it goes through a prism
    13·1 answer
  • What is needed to start a chemical reaction
    12·2 answers
  • Which is required for
    13·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!