# Is there a reaction pair for $mg \sin \theta$ on a inclined plane?

Is there a reaction pair for $mg \sin \theta$ on a inclined plane?

It is there for the normal force on a block on a flat plane, so is it there for $mg \sin \theta$ also?

• $mg \sin \theta$ is the reaction force by the plane. It's equal to the vertical component of the gravitational force. See khanacademy.org/science/physics/forces-newtons-laws/…
– user191954
May 19 '18 at 13:21
• How are you defining $\theta$? May 19 '18 at 16:12

$mg\sin\theta$ is the component of the gravitational force which is directed down the ramp.   It's exerted by the Earth on an object which is on the ramp.   The reaction force is the equal and opposite gravitational force exerted by object on the Earth.