The discussion revolves around calculating friction forces for a car on a flat surface, specifically addressing the forces required to initiate and maintain motion. The original poster mentions a car with a mass of 1326 kg and provides specific forces needed to move and stop the car, indicating a focus on static and dynamic friction.
Some participants have provided insights into the concepts of static and dynamic friction, while others have raised questions about the specific calculations being requested. The discussion is ongoing, with participants clarifying their understanding and addressing potential misunderstandings.
The original poster indicates a lack of information regarding the kinetic coefficient of friction, which is relevant to the calculations being discussed. There is also mention of an upcoming exam, suggesting time constraints on the original poster's ability to engage further.
CWatters said:If I have understood correctly, the problem statement is telling you that to overcome the static friction you need to apply 160N. However once it's moving you only need to apply >120N to keep it moving. (eg this is a problem about static and dynamic friction).
However is the question really asking you to calculate the "friction forces" or the "coefficients of friction" ?
If the latter, look at the wikipedia entry for coefficient of friction. Hint: It's a ratio.
Sorry but I might not be able to return to this thread later.
azizlwl said:According Newton's 2nd law,
Fnet=ma
Fnet==F1+F2+F3+ ...Fn
Forces are vectors, so they have magnitude and direction.
If you take vector force pointing to the right is positive(vector as an arrow) , then vectors pointing to the left as negative.
As for the friction, the direction is always opposite of the motion of the object.
The value can be calculated by multiplying the Normal force to the kinetic coefficient μ.