posted by sara .
An object of mass M = 911 g is pushed at a constant speed up a frictionless inclined surface which forms an angle θ = 50o with the horizontal as shown in the figure below. What is the magnitude of the force that is exerted by the inclined surface on the object?
Since there is zero acceleration, the net force on the object is zero.
You do not say what the angle of the applied force (with respect to the incline) is. Perhaps the "figure below" (which you do not provide) shows it. The answer depends upon it.