Cracking the SAT Physics Subject Test

(Marvins-Underground-K-12) #1

INCLINED PLANES


An inclined plane is basically a ramp. If an object of mass, m, is on the ramp, then
the force of gravity on the object, Fw = mg, has two components: one that’s parallel


to the ramp (mg sinθ) and one that’s normal to the ramp (mg cosθ), where θ is the
incline angle. The force driving the block down the inclined plane is the component
of the block’s weight that’s parallel to the ramp: mg sinθ.



  1. A block slides down a frictionless, inclined plane that makes a
    30 ̊ angle with the horizontal. Find the acceleration of this block.


Which Component?
To avoid drawing a free
body diagram for every
inclined plane problem,
remember that mg sinθ is
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