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
Yuri [45]
2 years ago
8

Falls resulting in hip fractures are a major cause of injury and even death to the elderly. Typically, the hip’s speed at impact

is about 2.0 m/s. If this can be reduced to 1.3 m/s or less, the hip will usually not fracture. One way to do this is by wearing elastic hip pads. (a) If a typical pad is 5.0 cm thick and compresses by 2.0 cm during the impact of a fall, what constant acceleration (in m/s2 and in g’s) does the hip undergo to reduce its speed from 2.0 m/s to 1.3 m/s? (b) The acceleration you found in part (a) may seem rather large, but to assess its effects on the hip, calculate how long it lasts.
Physics
1 answer:
Westkost [7]2 years ago
7 0

Answer:

-5.8868501529 m/s² or -5.8868501529g

0.118909090909 s

Explanation:

t = Time taken

u = Initial velocity

v = Final velocity

s = Displacement

a = Acceleration

g = Acceleration due to gravity = 9.81 m/s²

v^2-u^2=2as\\\Rightarrow a=\dfrac{v^2-u^2}{2s}\\\Rightarrow a=\dfrac{1.3^2-2^2}{2\times 0.02}\\\Rightarrow a=-5.8868501529\ m/s^2

Dividing by g

\dfrac{a}{g}=\dfrac{-57.75}{9.81}\\\Rightarrow a=-5.8868501529g

The acceleration is -5.8868501529 m/s² or -5.8868501529g

v=u+at\\\Rightarrow t=\dfrac{v-u}{a}\\\Rightarrow t=\dfrac{1.3-2}{-5.8868501529}\\\Rightarrow t=0.118909090909\ s

The time taken is 0.118909090909 s

You might be interested in
Estimate the number of atoms in 1 cm^3 of a solid
dexar [7]
Avogadro's number: 6.02 x 10^23 atoms is present in 1mol of a solid (i.e. 22, 400 cm3)

Hence, in 1 cm3, 6.02 x 10^23 /22400 atoms is present = 2 x 10 ^ 19 atoms.
7 0
3 years ago
1. Calculate the height of tree, 250 m away that produces
gtnhenbr [62]

Answer:

Explanation:

1.5/30 = x/250

x = 12.5 m

5 0
2 years ago
a person throws a ball in such a way that its speed is zero at one particular point in its path. How did the person throw the ba
Keith_Richards [23]

vertical! or in other words, up!


6 0
3 years ago
An engine takes in 2400 J of heat, and rejects 1880 J of heat into the air. What is the efficiency of the engine? (No Unit)
Galina-37 [17]

Answer:

.2166 repeating or 21.66% repeating

Explanation:

In attached image

8 0
3 years ago
In the Hunger Games movie, Katniss Everdeen fires a 0.0200-kg arrow from ground level to pierce an apple up on a stage. The spri
egoroff_w [7]

Answer:

a) v=99.8584\ m.s^{-1}

b) v'=99.366\ m.s^{-1}

Explanation:

Given:

mass of the arrow, m=0.02\ kg

stiffness constant of the bow, k=330\ N,m^{-1}

distance of pulling back the arrow on the bow from its mean position, \Delta x=0.55\ m

height of the apple targeted, h=5\ m

<u>Force on the arrow due to the stiffness of the bow:</u>

F=k.\Delta x

F=330\times 0.55

F=181.5\ N

Now the acceleration of the arrow upwards:

a=\frac{F}{m}

a=\frac{181.5}{0.02}

a=9075\ m.s^{-2}

a) For the course of motion when the arrow leaves the bow after the stretch is relaxed we consider that the arrow left the bow after its string goes to the mean position. During this phase the arrow also faces gravity in the downward direction.

Using the equation of motion:

v^2=u^2+2(a-g).\Delta x

where:

v= velocity with which the arrow leaves the bow

u= initial velocity of the arrow after it left

v^2=0^2+2\times (9075-9.81)\times 0.55

v=99.8584\ m.s^{-1}

b) Now when the arrow travels up then it is under a constant gravitational force acting opposite to the motion.

<u>Using eq. of motion:</u>

v'^2=v^2-2\times g.h

where:

v'= final velocity when the arrow hits the target

v= initial velocity after the arrow has been launched

v'^2=99.8584^2-2\times 9.81\times 5

v'=99.366\ m.s^{-1}

3 0
3 years ago
Other questions:
  • Question 6 (15 points)
    9·1 answer
  • A constant force is exerted for a short distance on a block of mass that is initially at rest on a horizontal frictionless plane
    12·1 answer
  • A fisherman notices that his boat is moving up and down periodically without any horizontal motion, owing to waves on the surfac
    5·1 answer
  • Boojho made light from a laser torch to fall on a prism. Will he be able to observe a band
    12·1 answer
  • it takes 1.4 minutes for Jonny to get to class which is a distance of 82 meters away s. what is Johnny’s average speed in second
    7·1 answer
  • What is the most likely elevation of point B?<br>a. 150 ft<br>b. 200 ft<br>c. 125 ft<br>d. 225 ft​
    5·2 answers
  • Andy has two samples of liquids. Sample A has a pH of 4, and sample B has a pH of 6. What can Andy conclude about these two samp
    8·1 answer
  • The density of ice is 917 kg/m^3, and the density of sea water is 1025 kg/m^3. A swimming polar bear climbs onto a piece of floa
    5·1 answer
  • How do lenses and mirrors compare in their interactions with light?
    13·2 answers
  • The equation to calculate density is D = m/v. For a liquid substance, which item increases as heat is applied?
    11·1 answer
Add answer
Login
Not registered? Fast signup
Signup
Login Signup
Ask question!