Hey,
Using newtons 2nd law of motion, why cars get better gas mileage than trucks? Please help asap:D

It's about mass... but of course Newton's 2nd law is not the only reason cars generally get better mileage.

Here's a good link/explanation of Newtons 2nd law that should help you if you're already familiar with basic Physics terms:

Newton's Second Law

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Newton's second law describes the relationship between force, mass, and acceleration using the following formula...

Force = mass x acceleration

Trucks are more massive than cars and require more force to accelerate them.

Let's say I want to accelerate the both of them at the same rate -- how about 5 m/s/s

A simple example calculation might look like this...

5000 N = 1000 kg x 5 m/s/s for the car if the car has a mass of 1000 kg

7500 N = 1500 kg x 5 m/s/s for the truck if it has a mass of 1500 kg

So we can see that it will take more force (and thus more gas used up by the engine) to accelerate the truck.

If you need greater detail, please let us know.

how about a reasonable guess?

we dont do homework, but will help with guesses and work you are doing yourself.

here's a start. Newtons second law gives us F(net) = m*a... or this could also be written as F(net)/m = a

so... the acceleration of the object is proportional to the net force on the object and inversely proportional to the mass of the object.

so what is a common difference between a car and a truck, in the context of this question and newtons 2nd?

this is a simplified problem, ignoring other factors, but the goal here is to use newtons 2nd... so you start with the definition or with formulas that describe the law.

Hey,
Thanks guys, no I wasn't using it fr homework, me and my teacher were having a discution about it, and we were just clearing up some things, I will try and explane it to him how you guys said and ill see if he is happy with the answer, but of course I won't take credit for your guys answers, ill tell him that 3 cool cats halped me out online. Thanks guys, check back later, maybe tomarow ill have another? Thanks again

Hi,
You have some great answers. Have you considered answering some questions as well as asking them? Just jump right in there, and share your experiences with someone asking a question.
Also, trucks many times have different gearing ratios than cars; causing them to be much less efficient using horsepower. Much of the horsepower, hence wasted gas, is lost between the engine, gear exchanger, transmission, rear differential, and wheels.

Good answers. Overcoming the initial inertia is the biggest problem then there is the problem of air resistance. A truck is (usually) not as dynamic as a car, and the faster you go the more air friction you experience. So the main factors of air friction are speed and cross sectional Area ( in a very simple nutshell). I am sure we have all felt that "pile" of air as we have passed a big truck. Pickups have some of the same problems. Just an amendment to the answers above