What is the Average Force Exerted on Occupants by Seatbelts in a Car Collision?

  • Thread starter Thread starter dan1995420
  • Start date Start date
  • Tags Tags
    Forces
AI Thread Summary
The average force exerted on occupants by seatbelts during a car collision can be calculated using the formula f=ma. For an 80 kg man in a car moving at 75 kph, the calculated force is approximately 8333.3 Newtons, based on a collision duration of 0.2 seconds. The weight of the car does not affect the force experienced by the occupants in this context. The discussion highlights confusion around the calculations but confirms the correct application of the physics formula. Understanding the dynamics of the collision is crucial for accurate force estimation.
dan1995420
Messages
1
Reaction score
0

Homework Statement


A model of an 80 kg man and one of a 25 kg child in a 1000 kg car and secured with seatbelts. The car was moving at 75kph as it crashed into a break wall.If the collision took 0.2s, calculate the average force exerted on each model by its seat belt

.

Homework Equations


f=ma


The Attempt at a Solution


im really confused, I am thinking that for the man: 80x20.8 (75000/3600), the divide by 0.2, so the force is 8333.3 Newtons?

Does the car's weight have anything to do with this?
 
Physics news on Phys.org
Hi Dan, welcome to PF!

:biggrin:
dan1995420 said:
im really confused, I am thinking that for the man: 80x20.8 (75000/3600), the divide by 0.2, so the force is 8333.3 Newtons?
Yes
Does the car's weight have anything to do with this?
No.
 
Thread 'Variable mass system : water sprayed into a moving container'

Thread 'Variable mass system : water sprayed into a moving container'

Starting with the mass considerations #m(t)# is mass of water #M_{c}# mass of container and #M(t)# mass of total system $$M(t) = M_{C} + m(t)$$ $$\Rightarrow \frac{dM(t)}{dt} = \frac{dm(t)}{dt}$$ $$P_i = Mv + u \, dm$$ $$P_f = (M + dm)(v + dv)$$ $$\Delta P = M \, dv + (v - u) \, dm$$ $$F = \frac{dP}{dt} = M \frac{dv}{dt} + (v - u) \frac{dm}{dt}$$ $$F = u \frac{dm}{dt} = \rho A u^2$$ from conservation of momentum , the cannon recoils with the same force which it applies. $$\quad \frac{dm}{dt}...
View full post »

Thread 'Struggling to understand the concept of this question (ice cube in water optics question)'

TL;DR Summary: I came across this question from a Sri Lankan A-level textbook. Question - An ice cube with a length of 10 cm is immersed in water at 0 °C. An observer observes the ice cube from the water, and it seems to be 7.75 cm long. If the refractive index of water is 4/3, find the height of the ice cube immersed in the water. I could not understand how the apparent height of the ice cube in the water depends on the height of the ice cube immersed in the water. Does anyone have an...
View full post »

Similar threads

Force exerted by a seatbelt, on driver, after collision
Replies
1
Views
9K
Help solving for average force please
Replies
14
Views
8K
Is average force dependent on the exertion time of force?
Replies
6
Views
2K
What is the magnitude of the average force that the air bag exerts on the driver?
Replies
7
Views
3K
To help reduce the severity of accidents [Average net force]
Replies
7
Views
2K
Net impulse and what objects exerts force
Replies
4
Views
3K
Collision with two cars (momentum and impulse)
Replies
6
Views
7K
Average force exerted by momentum
Replies
1
Views
2K
Physics120 car collision question
Replies
5
Views
12K
What Is the Average Force Exerted by a Recoiling Shotgun?
Replies
2
Views
2K

Hot Threads

Recent Insights

Back
Top