Can Human Forearm Bones Withstand the Stress of a High-Speed Car Crash?

In summary, this problem discusses the likelihood of an arm with a total cross-sectional area of 2.4cm squared and an effective mass of 3.0 kg being able to withstand a car crash with an initial speed of 80 km/hr and a deceleration of 0.005 seconds. To determine this, the compressional stress or pressure on the bones needs to be calculated, which can be found by converting all units to SI and using the equation for pressure (force/area). The average acceleration can also be found using the given information and then compared to the maximum compressional stress the bone material can withstand (16x10^7 Pa) to determine if the arm is likely to withstand the crash.
  • #1
frenchy7322
6
0
states of matter problem, me = :confused:

Total cross-sectional area of a load-bearing calcified portion of 2 forearm bones is approx 2.4cm squared. During a car crash, the forearm is slammed against the dashboard. the arm comes to frest from intiial speed of 80 km/h in 5.0 ms. If arm has effective mass of 3.0 kg and bone material can withstand a max compressional stress of 16x10^7 Pa, is arm likely to withstand crash?

Not sure on which equation to use due to not really getting the conceptual side of the question, please help!
 
Physics news on Phys.org
  • #2
The compressional stress is a pressure, which is a force per area. You have the cross-sectional area of the bones, so you need the force applied. You know the mass upon which the force is applied, so you need the acceleration. The average acceleration can be found from the information that the bones are brought to rest from an initial speed of 80 km/hr in 0.005 seconds. (You only care about the magnitude of this acceleration; it doesn't matter that the acceleration is negative.) Be careful about your units: everything should be converted to SI, since you want the pressure in Pascals.

How does the average pressure to which the bone is subjected during this deceleration compare to 1.6·10^8 Pa?
 

1. What causes a car crash?

A car crash is typically caused by a combination of factors, such as driver error, mechanical failure, road conditions, and weather conditions. Driver error is the most common cause of car crashes, including distracted driving, speeding, and driving under the influence of drugs or alcohol.

2. How is pressure involved in a car crash?

Pressure is involved in a car crash in several ways. The impact of the crash creates pressure on the vehicle and its occupants, which can cause injuries. The sudden deceleration of the car also creates pressure on the various internal components, which can lead to damage or failure.

3. How is pressure measured in a car crash?

Pressure in a car crash is typically measured in pounds per square inch (psi). This is a unit of pressure that is commonly used in the automotive industry. Pressure can also be measured in other units, such as pascals (Pa) or kilopascals (kPa).

4. Can pressure be reduced in a car crash?

There are several safety features in modern cars that are designed to reduce the amount of pressure experienced during a car crash. These include airbags, which help to absorb some of the impact and distribute it more evenly, and crumple zones, which are designed to deform and absorb energy to reduce the impact on the vehicle and its occupants.

5. How can pressure be calculated in a car crash?

Calculating the exact amount of pressure in a car crash can be challenging, as it depends on various factors such as the speed and weight of the vehicles involved, the angle and point of impact, and the overall design and condition of the vehicles. However, computer simulations and crash tests can provide a close estimate of the pressure experienced in a car crash.

Similar threads

Elastic Deformation through compression (stress)
    • Introductory Physics Homework Help
Replies
2
Views
5K

Hot Threads

Recent Insights

Back
Top