Thursday, January 12, 2012

The mass of a truck is 4 times the mass of a car. How should the acceleration of the truck and car compare?

The mass of a truck is 4 times the mass of a car. How should the acceleration of the truck and car compare if both experience the same net force?The mass of a truck is 4 times the mass of a car. How should the acceleration of the truck and car compare?
Just look at the equation for acceleration, which is: a = F/m, where "a" is acceleration, "F" is force, and "m" is mass.



If the truck and the car both have the same force (which would be the same size engines, in this case), then what will happen to "a," when "m" gets four times bigger?



Just make up some simple numbers, and plug them into the equation, to see what happens; like this:



a = F/m, so we'll let a=8, F=16, and m=2, just to start; like this:



8 = 16/2



Now, if the "m" gets four times bigger (turns into 8), like the problem says, then we'll have this:



2 = 16/8



This problem is illustrative of what would happen, if you took two little VW bug engines, and put one into a VW bug, and the other into an SUV, then had a drag race with them. Guess which one would win? You would have the same forces, trying to accelerate two different masses, and the outcomes kind of an obvious one, huh?



So, what happened to the "a?" It got four times smaller, right? Whenever you get kinda stuck, and can't seem to see what's happening in a physics equation, just play around with some simple numbers, then see what happens; that will usually help you to make sense of the whole thing. Of course, you have to know which equation to play around with, first...and that's usually the hardest part of solving a physics problem, for most students.



Hope that helped.The mass of a truck is 4 times the mass of a car. How should the acceleration of the truck and car compare?
the acceleration of the car should be 4 times higher than the acceleration of the truck. The mass of a truck is 4 times the mass of a car. How should the acceleration of the truck and car compare?
Interestingly enough we have Newton's Second Law to thank for this answer.

F(net)=m*a(net)

If both of the F(net) s are the same, then we can say the two values equal each other, so:

4m(truck)*a(truck)=m(car)*a(car)

In order to balance this the acceleration of the car must be 4 times the acceleration.

4m(truck)*a(truck)=m(car)*a(car)

We can't change the mass of the car because mass is constant.



I urge you to look at my source as it makes a better visual interpretation.

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