hello all Consider an experiment to prove that the acceleration in a certain direction on a given mass is directly proportional to the resultant force in that direction given that the given mass is constant. The acceleration can be measured using light gates. This resultant force can be varied by pulling on the given mass by elastic bands taking care to keep the extension of the band constant for a given resultant force. I heard a discussion re this experiment where the resultant force was provided by hanging a mass on a pulley. i do not think this is correct Physics. I would appreciate any reply whether I was correct in this. Thanks.