AP Physics C 2017

F (^) net on Inclines
A block of mass m is placed on a plane inclined at an angle θ . The coefficient of friction between the
block and the plane is μ . What is the acceleration of the block down the plane?
This is a really boring problem. But it’s also a really common problem, so it’s worth looking at.^2
Note that no numbers are given, just variables. That’s okay. It just means that our answer should be in
variables. Only the given variables—in this case m, θ , and m —and constants such as g can be used in
the solution. And you shouldn’t plug in any numbers (such as 10 m/s^2 for g ), even if you know them.
Step 1 : Free-body diagram.
Step 2 : Break vectors into components.