Phys 151 Lab 1
Jenna Simone
Experiment 1 – Putting on the Ritz
Objective/Purpose: The purpose of this lab was to understand motion and how graphical plots can represent motion.
Description of Experiment:For this experiment our group was assigned a specific graph to discuss and then to act it out by walking the motion that was shown on the graph, whether it be velocity or displacement.
Theory:The theory behind this experiment is to recognize and understand the five motional variables: distance, displacement, speed, velocity, and acceleration.
Equipment: There is no equipment for this experiment
Method: For this experiment we reviewed the five motional variables in order to make sure we understood their meanings. Then we were assigned a graph that as a group we had to discuss and figure out how to act it out. One person from our group then acted out the graph by walking the motion that was shown on the graph. We then reviewed the graphs as a class.
Results: Below are drawings of the graphs to answer questions 1 & 2 in the lab. The first graph is the corresponding velocity vs. time plot for the displacement vs. time plot in the lab. The second graph is the corresponding displacement vs. time plot for the velocity vs. time plot in the lab.
1.)Displ.
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Time
Vel.
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Time
2.)
Vel.
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Time
Displ.
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Time
Conclusion:Upon completion of this lab our group has gained a better understanding of the kinematic variables such as displacement made forwards and backwards, velocities produced forwards, backwards, slow or fast and the graphical representation of these actions. The experiment was successful because the visual experience was reinforced by the graphs, which increased our understanding of the five motional variables and their definitions.
Experiment 2 – Split Second
Objective/Purpose: To measure a person’s reaction time.
Description of Experiment: For this experiment we had to test each person’s reaction time in our group by having one group member hold a meter stick, and the other person holding their hand at the 50cm mark but not actually holding the meter stick. The first group member holding the stick was to drop the stick at any time and the group member holding their hand at the 50cm mark was supposed to catch the meter stick as soon as their reaction kicked in. We then calculated their reaction time by computing the difference between the 50cm mark and where the hand caught the stick.
Theory: When an object such as the meter stick is let go, it will fall straight to the ground. Newton determined that this force is constant, so the object is moving with constant acceleration. The following formulas prove this theory.
Acceleration: a = 10m/s^2 = rate of change of speed
Velocity: v = a.t = 10 t m/s
d = 1/2.10.t t = 5t^2m
Equipment: meter stick
Method: Refer to the description of the experiment. Record reaction time by computing the difference between the time the ruler was dropped and the time the ruler was caught for each group member. Repeat the exercise for each group member at least three times and then average out the distance traveled by using the formula above for d, which indirectly measures reaction time. Since d is in meters and t is in seconds the formula can be manipulated to give t = sqrt (0.2d)
Results: Below is the table of our group’s results:
Member / Initial Position / Final Position / Separation d / Reaction timet
Meredith Clark / .50m / .34m / .16m / Sqrt (0.2*.16) = .178
.50m / .72m / .22m / Sqrt (0.2*.22) = .209
.50m / .66m / .16m / Sqrt (0.2*.16) = .178
.50m / .70m / .20m / Sqrt (0.2*.20) = .2
.50m / .68m / .18m / Sqrt (0.2*.18) = .189
Mark Corpus / .50m / .60m / .10m / Sqrt (0.2*.10) = .141
.50m / .59m / .09m / Sqrt (0.2*.09) = .134
.50m / .57m / .07m / Sqrt (0.2*.07) = .118
.50m / .60m / .10m / Sqrt (0.2*.10) = .141
.50m / .60m / .10m / Sqrt (0.2*.10) = .141
Jenna Simone / .50m / .80m / .30m / Sqrt (0.2*.30) = .245
.50m / .75m / .25m / Sqrt (0.2*.25) = .224
.50m / .70m / .20m / Sqrt (0.2*.20) = .2
.50m / .72m / .22m / Sqrt (0.2*.22) = .2098
.50m / .68m / .18m / Sqrt (0.2*.18) = .1897
Conclusion: In comparing the data among our three group members, Mark has the quickest reaction time, followed by Meredith, and then Jenna. It can be said that since Mark has the quickest reaction time, and is a male, that gender plays a part. Since videogames are more popular among men, and they are thought to improve hand and eye coordination, so he might be more prepared for this type of exercise. Other circumstances such as athletic ability and or experience might play a part as well. If Mark has a background in soccer, tennis, baseball, hockey, etc. he would have a better reaction time because it is a skill that is worked on during training. His reaction time is significantly quicker then Meredith and Jenna. Even though Meredith is quicker then Jenna, their numbers are closer in relation then comparing Mark and Meredith. That is why gender could play a role in reaction time.
1.)Do You Want to be a Dollaraire?
Based on our data we would only bet someone if Mark was catching the bill. Jenna’s reaction time is not quick enough and based on the five trials, she would have dropped the dollar bill every time. Meredith’s reaction time is good, but not good enough to catch the dollar bill. Mark has the most consistent data and using his trials to judge whether his reaction time would be good enough, one can see that in several instances he would have caught the dollar bill.
2.)Don’t Let Granny Get Behind the Wheel!
Reaction time is an important factor in deciding how far behind a car you should drive because in the event you have to quickly put on your brakes to prevent an accident, you need enough space to allow for a reaction time and the vehicle to stop.
Average Speed = distance/time
60mph = d / 0.26seconds
d = 15.6 miles
1 yard = 0.00056818 miles
____1 yard_____ = ______x______
0.00056818 miles 15.6 miles
15.6 = 0.00056818x
x = 27,456.0000552 yards