1. It is incorrect.
The friction has to equal the force down the plane...right? The trolley has no net acceleration, so it must have no net force.
Net force= weight down plane - friction.
To determine if the statement is correct or not, you need to evaluate whether the equation is consistent with the given information. Let's break it down step by step:
1. Consider the force down the plane, which is the weight of the trolley. This force is equal to the mass of the trolley multiplied by the acceleration due to gravity (9.8 m/s²).
2. Now, let's analyze the friction force. Friction opposes the motion of an object and depends on both the coefficient of friction and the normal force acting on the object. The normal force, in this case, is the force exerted by the plane on the trolley, which is equal in magnitude to the weight down the plane.
3. According to your statement, the friction force must be equal in magnitude to the force down the plane for there to be no net acceleration. This means the equation you provided, "Net force = weight down plane - friction," is incorrect. In fact, the correct equation should be "Net force = force down the plane - friction."
4. If the net force is zero (no net acceleration), the force down the plane must be equal to the friction force. This ensures that the two forces balance each other out, resulting in a static situation with no net movement.
To summarize, your initial understanding about the need for the friction force to equal the force down the plane is correct, but the equation you stated is incorrect. The correct equation should be "Net force = force down the plane - friction."