1. The problem statement, all variables and given/known data An inclined plane, fixed to the inside of an elevator, makes a 40 angle with the floor. A mass m slides on the plane without friction. What is the acceleration relative to the block if the elevator is a)accelerating upwards .35g b)accelerating downwards .35g? c)constant speed 2. Relevant equations F=ma 3. The attempt at a solution 3. The attempt at a solution I know there's two accelerations I have to take into the account. The acceleration as the block slides down the incline, and the acceleration of the elevator. Combining these two, I can find the relative acceleration. I chose the reference frame to be titled so that the x-axis is along the incline. The thing I can't figure out is how the motion of the elevator affects the motion of the block. For example, when the elevator is accelerating upwards. Does the block accelerate upwards with it? From the block's force diagram I only have the normal force and mg down. the weight provides the acceleration down the incline but I have no clue what the elevator's acceleration does to the system. Any help would be appreciated. So lost though, how does the forty degree angle come into play?