In this study, we design and develop an experimental apparatus for studying the Newton’s first law, the normal force, the coefficient of friction and acceleration. The weight of an object was lying on an inclined plane wooden (acrylic and glass), a size of 15.0× 50.0 cm, were measured using strain gauge. Our experimental results showed that the weight of objects depended strongly on the inclined angle in the range of 15 to 60 degrees. The relevant results exhibited the decreasing weight of an object with increasing inclined angle. Moreover, the weight was evaluated as a function of an inclined angles θ , the relation of weight and the inclined angle could expressed as w1 = 100cosθ for m = 100g and w2 = 200cosθ for m = 200g. Therefore, we can conclude that, the change of a weight depends on an angle of the inclined plane, so we could define w mg = cosθ . Furthermore, we can see that it is in line with the normal force N = mg cosθ .
