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
blsea [12.9K]
3 years ago
10

When a 70 kg man sits on the stool, by what percent does the length of the legs decrease? Assume, for simplicity, that the stool

's legs are vertical and that each bears the same load.
Physics
1 answer:
allochka39001 [22]3 years ago
7 0

The diameter of one leg of the stool is missing and it's 2cm.

Answer:

(ΔL/L) = 0.00729%

Explanation:

If the Weight of the man is W, the weight will be distributed equally on the 3 legs and so the reactions for each leg will be W/3 or F/3.

Now, Youngs modulus(Y) of douglas fir wood is about 1.3 x 10^(10) N/m^2. Gotten from youngs modulus of common materials.

Now, weight of man is 70kg.

Now diameter of one leg is 2cm.so radius of one leg = 2/2 = 1cm = 1 x 10^(-2)m

Area for one leg is; π( 1 x 10^(-2)m)^2 = 3.14 x 10^(-4)m

Now as stated earlier, the force on one leg is; F/3.

Now F = mg = 70 x 9.81 = 686.7N

So, force on one leg = 686.7/3 = 228. 9N

Now we know youngs modulus(Y) = Stress/Strain.

Stress = F/A while Strain = ΔL/L

Therefore Y = (F/A) / (ΔL/L)

And therefore, (ΔL/L) = F/(AY)

So (ΔL/L) = 228.9/(3.14 x 10^(-4))x(1.3 x 10^(10)) = 7. 29 x 10^(-5)

When expressed in percentage, it becomes 0.00729%

You might be interested in
What makes it possible for us to see the moon from earth?
DENIUS [597]
D. Light from the sun is reflected off the moon's surface
3 0
3 years ago
Help meeeeeeeeeeeee ill mark brainlist to people
kvasek [131]

Answer: question 1 , would be one question 2 , would be 1 joule and number three would be number one and number four would be , power and last one would be, number two

Explanation: sorry if its wrong

5 0
2 years ago
1) According to the law of conservation of energy, A) an object loses most of its energy as friction. B) the total amount of ene
Blababa [14]
Your answer is C) <span> the potential energy of an object is always greater than its kinetic energy </span>
5 0
3 years ago
What is your opinion on Moonman? ( Do not delete this saying it is "racist". it is simply a character from a commercial called M
Leni [432]

Answer:

I think hes cool

Explanation:

8 0
3 years ago
Need help with the questons asap
mina [271]
Which questions? i need to see the actual question, did you like upload them to your profile now?
4 0
3 years ago
Other questions:
  • Why is there a peak in the graph between static and kinetic friction?
    15·1 answer
  • Which statement is true of an object in equilibrium
    6·2 answers
  • An object with a mass of 78 kg is lifted through a height of 6 meters how much work is done
    8·1 answer
  • A piston-cylinder assembly contains air at a pressure of 30 lbf/in2 and a volume of 0.75 ft3. The air is heated at constant pres
    15·1 answer
  • Amy walks 32 m right and then 12 m left. She turns and walks another 28 m right and then turns and walks 7 m left. What is Amy's
    11·1 answer
  • Last night, Shirley worked on her accounting homework for one and one half hours. During that time, she completed 6 problems. Wh
    11·2 answers
  • What is the main factor that influence how long a star burns
    13·1 answer
  • An element consists of two isotopes. The abundance of one isotope is 60.40% and its atomic mass is 68.9257 u. The atomic mass of
    15·2 answers
  • 4. A moped travels 20 kilometers in 30 minutes. Calculate its average speed in km/h?
    15·2 answers
  • PLEASE HELP!!!!
    10·2 answers
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!