The force of the fan used in the experiment is relatively constant during the experiment. If the mass is given and the acceleration computed, the force can be found. The actual force can be measured using a spring scale.
Then, by changing the mass, a new acceleration can be measured. This can also be checked with the spring scale to show that the law holds for all masses. The force can also be adjusted by rotating the fan on the fan cart away from the axis of motion and calculating the component in the direction of motion. The acceleration can be measured and checked with the spring scale. The fan force needs to be sufficient to make frictional forces negligible.
The force can also be adjusted by rotating the fan on the fan cart away from the axis of motion and calculating the component in the direction of motion. The acceleration can be measured and checked with the spring scale. The fan force needs to be sufficient to make frictional forces negligible.