Through the fan cart lab and hover disc lab that we did in our physics groups, we demonstrated and analyzed Newton's three laws of motion. In the hover disc lab, a device with a small fan at the bottom was used. This device could gravitate a few inches above the ground, counteracting friction. We described the relationships and natural forces that occur among the device, Earth, and two people who provided an outside net force. Interaction and free body diagrams can be used to map out the forces at work within this system. During the fan cart lab, we measured the amount of force a fan cart would project onto a sensor. We increased the amount of mass on the cart for every new trial as the distance and fan pressure remained constant.
Reflection:The fan cart lab and hover disc lab satisfies Newton's first law. (which states that an object moving at a constant speed will stay that way unless it experiences a net force) The fan, which eventually attained a constant speed could, theoretically, never stop or slow down unless it experiences a net force. The net force in this case was a person's hand or the electronic probe. The hover disc, when pushed, could maintain a constant speed because of its ability to gravitate above the ground and counteract friction.
Both labs also describe the Second Law. (a net force will accelerate an object) The fan attached to the cart provided a steady force by which the cart could move. When the fan pressure was increased or if someone applied their hand to the cart, it would experience acceleration. The harder the force that was applied on the hover disc, the faster it would propel forward and the faster it would accelerate if it had already been moving.
The fan cart and hover disc labs illustrate Newton's third and final law of motion (for every action, there is an equal and opposite reaction). When the cart was forced against the sensor, it nearly bounced back to the same position that it started at. Some energy was lost as heat on the track. When a person pushes the disc against a wall, the harder they push the disc, the greater the distance of the recoil.
Real-World Connection:In regards to Newton's Third Law, a person discharging a firearm is a prime example. Guns with greater firepower produce much greater recoil and apply an equal and opposite force back to the shooter. A shotgun produces much greater recoil than a pistol.
Fun Fact: Newton first published his work, which included his three laws of motion, in the book Philosophiae Naturalis Principia Mathematica on July 5, 1687.
