Speed bump reaction force on a car

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Homework Help Overview

The problem involves a car with a specified mass and speed encountering a speed bump, raising questions about the forces acting on the front axle during impact. The context is rooted in dynamics and the application of Newton's laws.

Discussion Character

  • Exploratory, Assumption checking, Conceptual clarification

Approaches and Questions Raised

  • Participants discuss the interpretation of the problem, questioning whether it should focus on impulse rather than force. There are considerations about the missing information and the impact of variables like tire rigidity on the force experienced.

Discussion Status

The discussion is ongoing, with participants exploring different interpretations of the problem. Some have suggested working symbolically and raising questions about the directions of impulse and tire movement post-impact. There is no clear consensus yet on the approach to take.

Contextual Notes

Participants note that the problem may lack certain details necessary for a complete analysis, and there is an acknowledgment of the complexity introduced by various assumptions.

Duffelmop
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Homework Statement


Hi I need to solve the next problem: a car with a total mass of 1950KG hits a speed bump at 19,4m/s. The speed bump is 0,05m high and has a angle of 45°. The car hits the bump with the front axle first. How much force acts on the front axle on the moment of impact.

Homework Equations


I started with Newton's law... but I totally messed it up...
Also did some search work, but it made it only more complex for me:
http://www.shimrestackor.com/Code/User_Manual/Sections/Suspension_Velocity/suspension-velocity.htm

The Attempt at a Solution

Sorry for my bad english.
 
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Are you sure you have quoted the question exactly? Seems like it should be asking for impulse, not force.
 
haruspex said:
Are you sure you have quoted the question exactly? Seems like it should be asking for impulse, not force.

They asked us to answer how much force was acting on the car in those conditions. It was an exam question this morning, and i really couldn't solve it. It seems for me like there is something missing...
 
Duffelmop said:
They asked us to answer how much force was acting on the car in those conditions. It was an exam question this morning, and i really couldn't solve it. It seems for me like there is something missing...
The force is indeterminate, since it will depend on e.g. the rigidity of the tyres. Assume it means impulse.
It's best to work symbolically and only plug numbers in at the end. Let the car be moving initially at speed u, have mass m, and tyres radius r.
Let the impulse from the speed bump be J and the horizontal component of the car's speed immediately afterwards be v.
For simplicity, we can take the car's mass as being m/2 at the middle of the front wheels and m/2 at the middle of the back wheels.
1. In what direction will the impulse be?
2. In what direction will the front tyres be moving immediately after impact, and at what speed? (Assume no bounce.)
3. In what direction will the rear tyres be moving?

Can you write a conservation equation to relate these?
 

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