Lab 4

For lab 4 we were asked to find the initial acceleration of an elevator when it starts and stops. To do this we were given a force probe attached a 550 gram weight and stand that would measure the change in force as the elevator accelerated. 

Before we could do this we had to first calculate the amount of force that gravity was putting on the probe itself in order to subtract it from our findings in the elevator. After zeroing the probe we found that gravity placed roughly 5.1 newton’s of force on the probe, with this information in hand we quickly sketched a set of a motion diagram, force diagram, and force addition diagram. We calculated that the elevator would have its forces cancelled out by both the tension in the cable and the force of gravity until the moment of acceleration, at which point the motor in top of the elevator shaft would either increase tension to make the elevator go up or decrease it to make it stop and equalize. We would then be able to calculate the elevators acceleration by dividing the change in force by the velocity, giving us the acceleration.

Armed with this information we proceeded to the elevator and took a single reading from the start of the elevators trip to the bottom to its stop at the bottom floor that provided the following chart from logger pro.

From this information we were able to discover the force at the time of acceleration at the elevators beginning and ending. Logger pro calculated the force at approximately 5.1 at the beginning as the elevator traveled downwards and increased to 5.8 at its stop in order to counteract its velocity downwards and 5.3 for its constant movement. We then subtracted the constant force of gravity, 5.1 from each reading to find the change in force, calculating to -.3 net force for the initial downwards acceleration and a .4 increase for the upwards acceleration to cease moving and a constant .2 difference. 

We then plugged this information into the formula Weight*Acceleration=Force, giving us 550*A=5.1, which after dividing the force by the weight to isolate acceleration gave us 0.009 Meters per second for start, and then did the same for its acceleration to stop, calculating to 0.010, keeping the force relatively the same for the elevator. To calculate the speed of the elevator we divided this number by the weight of the weight attached to the recorder in kilograms, calculating that the average speed of the elevator was .36 Meters per second. A fairly comfortable pace for an elevator that takes roughly 9 seconds to go between floors.

Possible problems.

Gaining the information for an elevator is not always exact as it can be difficult to time the movement of the elevator with when the graph starts and ends, we were lucky, but we may have missed some critical data. Additionally we always needed to take the averages of the information and that can sometimes be skewed by large temporary readings, like the short hikes that the graph shows for the initial movements of the elevator.

Lab 3: Forces

For lab 3 we experimented with forces and motion and how they could affect and change the acceleration and velocity of an object. The final result of this was an experiment that monitored the change in velocity as more weights were added to double the amount of force being used to pull the slide, as can be seen below. In order to create a controlled and uncontrolled system to compare the results to we used compressed air to create a friction-less environment and then used the rail base to compare how friction can change an objects velocity.

To support these findings we also experimented with changing and varying the amount of newtons to pull a car and see how its acceleration changed, seeing that the value increase with the amount of force applied.

 

These experiments tied into the very first experiment we did where we experimented with changing the location and amounts of force exerted on a bowling ball to see how we could influence it. constant force would create constant acceleration while when provided with a much more loose or reduced friction environment, or constantly maintained force to produce a constant velocity. The secondary experiments supported this with the first one providing an example of changing force and the second and example of constant force, supporting the statement that all motion is based on the force behind it.

Lab 2, APPLICATION EXPERIMENT: WHAT KIND OF MOTION?

For lab 2 we were assigned to find whether a provided coffee filter would fall at a constant speed,
constant acceleration, or changing acceleration. In order to do this we decided to place a motion detector on the floor and align said coffee filter with the reader above it and drop it onto the motion detector. After several tries that caused the filter to drift off of the scanner and disturb our results we elected to place several filters together in order to give the object more mass and allow it to fall straighter without being disturbed by passing persons or air currents. The result of this can be found below.

Our results were then recorded and we compared the slope of the graph to calculate its constant rate of motion to determine its rate of motion and if that rate changed or was constant, representing whether its fell constant speed, constant acceleration, or changing acceleration.

We began with an over view of the movement.

As can be seen on the graph the coffee filter slowly begins to accelerate in its constant motion due to its increase in its acceleration downwards. this rules out the question of whether the filter falls at constant speed.

In these next two we can see that the velocity and position are constantly changing, by definition ruling out the possibility of constant acceleration as the rate is not constant, rather changing. Thus we can surmise that the coffee filter falls with a changing acceleration until it hits the floor, at which point it achieves a quite constant and unchanging acceleration of zero as it is resting in place.

Problems;

While we did the best we could we acknowledge that there are some problems with this form of measurement. Firstly the most common problem was that the filter was too light and had a tendency to drift off the scanner, invalidating our readings, this can be caused by a simple drift to the right or even a person walking by and disturbing the air. Additionally we were dropping the filter from a height of roughly one meter, a height that serves well as a basis for a smaller measurement but does not allow for terminal velocity to take effect, possibly changing the experiment.

Lab 1

In order to discover what our average walking speeds were we decided to measure how fast we walk towards the motion detector 3 times and average the 3 to find an average speed.

In order to calculate the speed we measured how long it took us to cover the distance, for example if we covered the 2 meters in 2 seconds then we walked a meter per second for that test. In order to obtain a more accurate measurement we proceeded to repeat this experiment 3 times and average the results to obtain a more accurate answer.

My 3 results were, 1. 3 meters in 4.4 seconds, or 1.4 meters per second, 3 meters covered in 4.2 seconds, or also 1.4 meters per second, and finally 3 meters covered in 4 seconds, or 1.3 meters per second.




Overall I covered 9 meters in 12.5 seconds, and possessed speeds of 1.4, 1.4, and 1.3 meters per second, so by averaging that number by dividing it by the 3 tries we get my average walking speed to be 1.36 meters per second.