in high school , i solve friction questions by making FBD but recently i got a doubt while imagining a situation
suppose there is a block of mass 4kg kept on ground and we apply a force of 20N and lets assume the limiting friction is 14N and kinetic friction is 12N , so the block will start sliding and when we make equation of motion for this block we will get
20N – 12N = 4a
a = 2m/s²
so the block will have acceleration 2m/s²
but if we think of what will happen after our force, the block will stop after sometime
so what does actually happen after this 2m/s² acceleration which causes the block to stop , it will be friction obviously ( if we neglect air resistance ) but does friction keep resisting the motion of block and if yes then can anyone explain thoroughly what exactly happens cause this was never taught in our class ,
thanks
In: Physics
If you keep applying a force, the block will keep moving. If you stop applying force, the block will slow down and then stop. The reason it slows down is because there’s still kinetic friction acting opposite to the direction of the block’s motion. And when you stop applying the force, there’s nothing to work against friction. So the friction causes negative acceleration until the block becomes stationary.
Friction is essentially interactions between objects and the surface they’re sitting on. Imperfections in the bottom of the block and the surface of the floor tend to oppose the block’s motion. The rougher a surface is, the more friction you’ll get.
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