Force Breakdown for accelerating a car

AI Thread Summary
In a discussion about the forces involved in accelerating a car to 100 mph, it was noted that inertial forces require the most energy to overcome, significantly more than aerodynamic drag, especially for a vehicle with a low drag coefficient of 0.15. The graph presented highlights that while aerodynamic drag is relatively minor, mechanical losses and rolling resistance also contribute to the overall power draw. Participants acknowledged that the impact of inertia is substantial at lower speeds, but as speed increases, aerodynamic forces begin to play a more significant role. The conversation emphasized the importance of acceleration rates in understanding these dynamics. Overall, the analysis suggests that inertial forces dominate energy requirements during initial acceleration phases.
robinfisichel
Messages
39
Reaction score
0
So I've been doing a mini investigation into the power draws on a car accelerating up to a aroudn 100 mph and came up with this graph.

I never really thought about it before but it appears from this graph that inertial forces (here i have only taken into account the acceleration of the main mass, not including any rotating component inertial draws) require the most energy to overcome.

Aero drag is relatively small in comparison, though the Cd of this vehicle is only 0.15.

The other lines are some mechanical losses (produced from an emiprical formula) and rolling resitance of the tyres.

would people agree with this?

Y axis = Newtons
X axis mph
 

Attachments

  • Force_breakdown.jpg
    Force_breakdown.jpg
    26.2 KB · Views: 541
Engineering news on Phys.org
Yeah, that makes sense, especially with that VERY low drag coefficient. Although keep in mind, that it depends on your acceleration. If you have a fast enough missile, the inertia will be taking up most of the force until even thousands of mph, where as in this car you can already see the aero loads starting to catch up with the inertial ones...
 
Posted June 2024 - 15 years after starting this class. I have learned a whole lot. To get to the short course on making your stock car, late model, hobby stock E-mod handle, look at the index below. Read all posts on Roll Center, Jacking effect and Why does car drive straight to the wall when I gas it? Also read You really have two race cars. This will cover 90% of problems you have. Simply put, the car pushes going in and is loose coming out. You do not have enuff downforce on the right...
Thread 'Physics of Stretch: What pressure does a band apply on a cylinder?'
Scenario 1 (figure 1) A continuous loop of elastic material is stretched around two metal bars. The top bar is attached to a load cell that reads force. The lower bar can be moved downwards to stretch the elastic material. The lower bar is moved downwards until the two bars are 1190mm apart, stretching the elastic material. The bars are 5mm thick, so the total internal loop length is 1200mm (1190mm + 5mm + 5mm). At this level of stretch, the load cell reads 45N tensile force. Key numbers...
I'm trying to decide what size and type of galvanized steel I need for 2 cantilever extensions. The cantilever is 5 ft. The space between the two cantilever arms is a 17 ft Gap the center 7 ft of the 17 ft Gap we'll need to Bear approximately 17,000 lb spread evenly from the front of the cantilever to the back of the cantilever over 5 ft. I will put support beams across these cantilever arms to support the load evenly

Similar threads

Back
Top