Energy required to start motion
Energy required to start motion
(OP)
I'm out of my area here, but I'm trying to calculate the energy required to start a car moving. How do you calculate the energy required to overcome static friction and the cars inertia. Thanks in advance, Chris





RE: Energy required to start motion
Second, F=ma
RE: Energy required to start motion
There will be a lot of variables, like tyre pressure, temprature of lubricants, brake drag, nature of surface, wind, inclination of surface bearing preloads, time since last moved etc. This will give static friction.
The inertia is easier. As MintJulep says F=MA, however there is the linear acceleration of the entire mass, and the moment of inertia of the rotating parts.
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RE: Energy required to start motion
RE: Energy required to start motion
RE: Energy required to start motion
Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips Fora.
RE: Energy required to start motion
http://en.wikipedia.org/wiki/Rolling_resistance
RE: Energy required to start motion
F=m*a+m*g*tan(theta)+m*Crr*g+a bit more for driveline drag etc+1/2*Cd*A*rho*v^2
at v=0, and a~0 the first and last terms are irrelevant
Problem is, that is for rolling friction, not stiction.
When as tire is cold and stationary the plies move around and then stick together, deforming the tire. That's why they can feel bumpy first thing in the morning.
Cheers
Greg Locock
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RE: Energy required to start motion
F = weight x sine (theta)
RE: Energy required to start motion
Like several people stated, you are looking for Force as in F=ma.
Work/Energy will be the amount of Force through a distance.
Power is Work over time. You need Power to accelerate the mass up to a specified speed in a specified time.
So.....what do you want to do? Just move a vehicle off of its stiction point to its first motion, or move it up to a specific speed? Those are two different things with different amounts of force/power/work/energy.
TygerDawg
Blue Technik LLC
Advanced Robotics & Automation Engineering
www.bluetechnik.com
RE: Energy required to start motion
RE: Energy required to start motion
Mike Halloran
Pembroke Pines, FL, USA