Measure the length (d) and the vertical height (h) of the incline plane. Measure the distance from the bottom of the inclined plane to the top where your object starts moving. Make all your measurements in meters. Know that 1 inch = 0.0254 meters.
Divide the height "h" by the length "d" to find sine of the angle (Q) of the inclined plane. Sin (Q) = h/d
Use Newton’s Second Law--F (forces) = m (mass)*a (acceleration)--that states that the acceleration is directly proportional to the force applied to the object. The force pulling the object down has a magnitude of m*g*sin (Q). Therefore: m*a = m*g*sin (Q), where "g" is acceleration due to gravity and equals 9.8 m/s^2 (constant). Solve for “a”: a = g*sin (Q). Multiply 9.8 m/s^2 by sin (Q) from Step 2 to find the acceleration of object at the bottom of the incline in meters per second^2.
Include in your equation the values of time when given or measured. Find the acceleration of the object from the relationship between acceleration, distance (d) and time (t): a = 2*d/t^2. Use this formula to find the acceleration of the object at any time the object traveled down the incline. Use the distance "d" as the length the object traveled in the given time frame.