PCS-125-Lab 1 (2)

pdf

School

McMaster University *

*We aren’t endorsed by this school

Course

2B03

Subject

Physics

Date

Apr 3, 2024

Type

pdf

Pages

11

Uploaded by DukeFrogMaster778

Report
Pre Lab Questions: 1. ? = ? ? If the amplitude is varied it will have no effect on the angular frequency. If the mass is increased then the angular frequency will become smaller, if the mass is decreased then the angular frequency will become bigger. If the spring constant is increased then the angular frequency will also increase, if the spring constant is decreased then the angular frequency will decrease. This is due to the angular frequency equation .
2.In order to determine the spring constant I would plot the frequency as the y axis and the mass as the x axis. Calculating the slope of that graph should yield the spring constant. Introductions: The objective of this lab is to see how the period of oscillations changes when changes are made to a spring-mass system the secondary object of this lab is to try and determine the spring constant from the data collected. In the first experiment, the spring constant and the mass both will stay fixed and the amplitude of the spring-mass system will change, the period of oscillation will be observed and recorded as the amplitude is changed. In the second experiment, the amplitude and the spring constant will both stay fixed and the mass of the spring-mass system will be changed. Again the period will be observed and recorded as the mass changes. In the third experiment, the spring constant will be fixed and the mass of the spring-mass system will be changed. The displacement of the spring will be recorded as the mass changes, this displacement will be used to calculate the spring constant later on. Theory:
In the lab the main equation used was ( . This equation shows how the period of an 𝑇 = 2π ? ? ) object in simple harmonic motions changes when the mass and the spring constant are changed. The derivation of this equation is shown below. It is known that to describe and understand simple harmonic motion this equation is used. ???𝑎?𝑖?? 1: ?(?) = 𝐴𝑐??(?? + Φ) It is also known that since cos(x) is a periodic function then the following equation is true. ???𝑎?𝑖?? 2: 𝑐??(?) = 𝑐??(? + 2π) Combining equation 2 and 3 will allow us to derive the period equation. ???𝑎?𝑖?? 3 : 𝐴𝑐??(?? + Φ) = 𝐴𝑐??(?(? + 𝑇) + Φ) ???𝑎?𝑖?? 4: ? = ?? + Φ ???𝑎?𝑖?? 5: 𝑐??(?? + Φ) = 𝑐??(?? + ?? + Φ) Sub equation 4 into equation 5 Equation 6: 𝑐??(?) = 𝑐??(? + ?𝑇) Comparing equation 6 and 2 we can see that ?𝑇 = 2π Simply solve for T and we get the period equation to be 𝑇 = ? = 2π ? ? I predict that for experiment one the period will not change since in experiment one the only thing that we are changing is the amplitude and as seen from the equation the amplitude will not affect the period. In experiment two I predict that the period will increase as the mass increases. And for the third experiment, I predict that the displacement will increase as the mass increases. Producer: Experiment 1:
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
  • Access to all documents
  • Unlimited textbook solutions
  • 24/7 expert homework help
Step 1: Make sure that the damping is set to zero, the gravity is set to 9.8m/s^2, the spring constant is set to the second increment and the mass is set to 50g. Step 2: Place the mass on the spring and use the ruler tool and line it up so the zero is at the start of the mass. Step 3: Make sure the simulation is stopped and pull down the mass to the desired amplitude. Step 4: Start the simulation and use the timer tool to record 10 oscillations and do this three times. Step 5: Take the average for the three trials and divide by 10 to get the desired period. Step 6: Change the amplitude and repeat steps 4 and 5 Experiment 2: Step 1: Make sure that the damping is set to zero, the gravity is set to 9.8m/s^2 and the spring constant is set to the second increment. Step 2: Place the mass on the spring and set the amplitude to 0.2 meters Step 3: Start the simulation and use the timer tool to record 10 oscillations and do this three times Step 4: Take the average for the three trials and divide by 10 to get the desired period. Step 5: Use 5 more different masses and repeat steps 3 and 4 Experiment 3: Step 1: Make sure that the damping is set to zero, the gravity is set to 9.8m/s^2 and the spring constant is set to the second increment. Step 2: With no mass on the spring take the ruler tool and place it so the zero end of the ruler is at the end of the spring
Step 3: Place the first mass and measure the distance between the original position of the end of the spring and the new positions. This will be your displacement for whatever mass chosen. Step 4: Repeat steps 3 using 5 more different masses Stept 5: Calculate the force of gravy for each of the masses used. Results and calculations: Experiment 1: Amplitude vs Period Mass is fixed at 0.05kg K is fixed at the second increment Amplitude (m) Time For Ten Oscillations Trial 1 (s) Time For Ten Oscillations Trial 2 (s) Time For Ten Oscillations Trial 3 (s) AverageTime For Ten Oscillations (s) Average Period (s) 0.1 6.37 6.32 6.35 6.35 0.635 0.005 0.2 6.30 6.35 6.37 6.34 0.634 0.005 0.3 6.40 6.33 6.37 6.36 0.636 0.005 0.4 6.35 6.30 6.37 6.34 0.634 0.005 0.5 6.33 6.33 6.34 6.33 0.630 0.005
Table 1: Amplitude and Period For each trial the time for ten oscillations was measured instead of just one. This is because it reduces the risk of human error (stopping the stopwatch) involved with the experiment. As expected the measured periods for different amplitudes are more or less the same. This is because the equation for the period ( does not include the amplitude therefore it is 𝑇 = 2π ? ? ) inferred and shown that changing the amplitude will not have any effect on the value of the period. The uncertainty for the period will be 0.005 Experiment 2: Mass vs Period Amplitud is fixed at 0.2m. K is fixed at the second increment. Mass(kg) Time For Ten Oscillations Trial 1 (s) Time For Ten Oscillations Trial 2 (s) Time For Ten Oscillations Trial 3 (s) AverageTim e For Ten Oscillations (s) Average Period (s) Average Period^2 (s) 0.05 6.32 6.33 6.35 6.33 0.633 0.005 0.400 0.005 0.1 8.92 8.90 8.90 8.91 0.891 0.005 0.0.794 0.005 0.15 10.92 10.93 10.88 10.91 1.09 0.005 1.19 0.005 0.2 12.62 12.65 12.63 12.63 1.263 0.005 1.59 0.005 0.25 14.10 14.13 14.11 14.11 1.411 0.005 1.99 0.005
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
  • Access to all documents
  • Unlimited textbook solutions
  • 24/7 expert homework help
0.3 15.43 15.42 15.43 15.43 1.543 0.005 2.38 0.005 Table 2: Mass And Period Graph 1: Average Period Squared vs Mass To get the spring constant k we first need to look at the period equation ( . We can 𝑇 = 2π ? ? ) manipulate this equation to make it relate to the slope of the graph. Currently, the slope of the graph represents . So the period equation was manipulated to make the slope useful. After the 𝑇 2 ? manipulation the period equation looked like this . After the slope is known ( ) then 𝑇 2 ? = 4𝜋 2 ? 𝑇 2 ? the spring constant can be solved for. Calculation for the spring constant: 𝑇 2 ? = ????𝑒 𝑇 2 ? = 0.4 0.05 = 8
8 = 4𝜋 2 ? 8? = 4𝜋 2 ? = 4𝜋 2 8 ? = 4. 93𝑁/? Experiment 3: Force of gravity vs Displacement K is fixed at the second increment Mass(kg) Displacement or Δy (m) Force Of Gravity (N) 0.05 0.11 0.0005 0.49 0.1 0.2 0.0005 0.98 0.15 0.31 0.0005 1.47 0.2 0.4 0.0005 1.96 0.25 0.5 0.0005 2.45 0.3 0.6 0.0005 2.94 Table 3: Mass, Displacement And Force Of Gravity
Graph 2: Force Of Gravity vs Displacement Uncertainty was calculated by taking the smallest increment on the measuring device(ruler) which was 1mm and dividing it by 2 which resulted in an uncertainty of 0.5mm. A total of 6 masses were used since that was the amount used in experiment 2. Calculation for the spring constant: There are two ways of calculating the spring constant in this experiment. The first is to calculate the slope of the graph (force of gravity vs displacement). The second is to use Hooke's law to isolate for the spring constant. Both methods will be shown below. First method: Slope = k ????𝑒 = (?2−?1) (?2−?1)
Your preview ends here
Eager to read complete document? Join bartleby learn and gain access to the full version
  • Access to all documents
  • Unlimited textbook solutions
  • 24/7 expert homework help
(?2−?1) (?2−?1) = ? (2.94−2.45) (0.6−0.5) = ? 4.9 N/m ? = Second method: Assume that up is the positive y direction ?? =− ?Δ? − ?𝑔 =− ?Δ? ?𝑔 = ?Δ? ?𝑔 Δ? = ? ? = (0.3)(9.8) 0.6 ? = 4. 9𝑁/? Comparing the spring constant from experiment 2 (4.93N/m) and from experiment 3 (4.9N/m) it is shown that they are more or less the same. Conclusions: In experiment one, the amplitude of the spring-mass system was changed while the mass and the spring constant remained the same. This resulted in the period not changing at all for any value of amplitude that was tested. This was because the amplitude (A) is not in the period equation so no matter how much the amplitude was changed the period remained more or less 𝑇 = 2π ? ? constant. In experiment two the mass of the spring-mass system was changed while the amplitude and the spring constant remained the same. This resulted in the period increasing as the mass of the spring-mass system increased. This data was then recorded and graphed, with the y axis being the period squared and the x-axis being the mass. The graph that was created was a linear one, the slope of which represent the
period^2 divided by the mass . This was then used to isolate for the spring constant k ). ( 𝑇 2 ? ) ( 𝑇 2 ? = 2 ? The spring constant for the second experiment was 4.93N/m. In the third experiment, the amplitude and the spring constant remained the same while the mass of the spring-mass system was changed. For every new mass on the spring-mass system, the displacement that it had on the system was recorded. This data was then graphed with the force of gravity being on the y-axis and the displacement being on the x-axis. This resulted in a linear graph, the slope of this graph would be the value of the spring constant which ended up being 4.9N/m. From this lab, there are three important discoveries that were made. The first being that the amplitude has no effect on the period of a spring-mass system moving is simple harmonic motion. The second is that the spring constant can be found if we simply know the period and the mass. The third is that the spring constant can also be found using Hooke's law if we know the displacement that a certain mass has on a spring-mass system and the weight of that mass.