Newton's Second Law

The purpose of this experiment is to gain a better understanding of Newton's second law using Data Studio and the Dynamics Track. In this experiment the students will use a fan to propel a cart towards a motion sensor. The data recorded from this experiment will allow the students to measure the acceleration of the cart with different combinations of masses added. The students will confirm the force calculated by measuring it directly with a force sensor. Also, the magnitude of the frictional force on an object at rest, as well as the kinetic friction once that object is brought to a constant velocity will be observed as well. Newton's second law is the sum of the forces equals mass multiplied by acceleration. Some object with more mass requires a greater force in order to attain the same acceleration as an object with lesser mass. The force used to accelerate the cart is a fan motor; the blades exert a force on the air which exerts an equal and opposite force on the blades. The reaction force is what enables the cart to move forward. Kinetic friction of an object acts in the opposite direction of the velocity of the object; in theory without friction objects would not stop moving once they started.

In the first part of the experiment the students set the cart at the end farthest away from the motion sensor, with the fan propelling air away from the motion sensor. One student turned the fan on while the other presses start to record the data in Data Studio. The cart is released and had to be caught before it hit the motion sensor, then one person presses stop in Data studio. For the graph produced the students had to highlight the points that followed a straight line. The end points were not to be included. The same procedure was done with masses of .2, .4, .6, and .8 kg added to the cart. Once the mass and acceleration values were recorded, then the force exerted on the cart needed to be calculated for each run. In part two a force sensor was connected to the cart with a string. The force sensor needed to be parallel to the track to get accurate results. Before pressing start to record data the tare button on the force sensor needed to be pressed to establish a zero force. While one student presses start another turns on the fan to record the force vs. time. When it reached a constant value the stop button was pressed. Then the students had to find the average force and standard deviation excluding the end points of the data. In last