Lab 8:Energy (Discussion)
In this lab, the goal was to prove the law of conservation of energy. In order for this to be true, GPEi and KEf had to be equal. After 20 trials of collecting data (final velocity (m/s), angle (theta), final and initial displacement (m) ) we found the average displacement (m) to be .89m. Using the average displacement, we were able to calculate the height of the track using the equation h=dsin(theta). We then plugged in all of our information into the equation gh=1/2v^2. The goal was to have the GPEi and KEf close to one another if not 0 in order to prove the law of conservation of energy. If the numbers weren’t exactly 0, it was due to uncertainty in the GLX and our rounding of sig figs. Using the GPEi and KEf we found the perfect difference which showed us the accuracy of our data. If I were to do this lab again, I would be more careful about sig figs because it effects the calculations.
Lab 8:Energy (Calculations)
Derivation of the Conservation of Energy:
(KEf-KEi) + (GPEf-GPEi) =0
KEi=0
GPEf=0
KEf=GPEi
mgh=1/2mv^2
gh=1/2v^2
example: (trial 1)
gh=1/2v^2
(9.8m/s^2)(.10m)= 1/2(1.43m/s)2
.98=1.02
Calculations for height:
h=dsin(theta)
example: (trial 1)
(.89m)sin(6.5deg)=.10m
Calculations for percent difference:
(GPE-KE)/(GPE)=perfect difference (%)
example: (trial 1)
(1.02-.98)/(.98)=4.1%
Lab 7: Friction (Discussion)
The purpose of this lab was to determine the coefficient of friction. In the lab, we tested the friction of three objects: a cart on a ramp (frictionless ramp), box being pushed on a table, and a ball being rolled on a table. The lab was challenging because it was hard to collect good data from the objects. The ball especially was difficult to use because it was hard to roll the ball in a straight line so the GLX could measure its acceleration. The table had much more friction than the ramp because the ramp was created almost frictionless, unlike the table. As we can see from our results, the box had the most friction. “µ” and acceleration have a direct relationship because as one increase, the other did as well. From the lab I learned that the mass of an object doesn’t affect the friction. As seen when we changed the mass of the cart from 500g to 1000g, the friction stayed nearly the same.
Lab 7: Friction (Friction (µ) Calculations)
Friction Calculations:
formula: µ= (-acceleration/g)
trial 1 example: µ=((-)-.0152(m/s2)/9.8(m/s2))
µ=.0016
