![]() Putting something to hit (and make a sound) at the end of the motion is easier. When releasing objects to begin motion, one needs a bit of consideration how to accurately associate a sound with the moment of release. Any digital sound recorder from which the data can be graphed and zoomed in on can be a much more accurate timer than a manually operated stopwatch. The technique works well for everything from a falling ball (the linker paper) to potatoes shot from a cannon, to bullets in flight to using echoes to measure the speed of sound. We've used an acoustic technique to make accurate lab timing measurements in various situations where a clear sound can be associated with the needed start and stop times. You should have persevered until you got more consistency (or so many measurements that taking an average should be reasonably reliable). 47, you could have realized this implied the measurements were too inaccurate. ![]() I'll add that there's a useful lesson here. Was this checked?Įdit: I see Orodruin beat me to the post (not unusual). The next most likely source of error is whether the base of the ramp has horizontal. A statistical analysis might reveal that the 90% error range is something like. 47, it is clear that there is considerable uncertainty in the value. The only time measurement that looks about right is the. But this still produces speeds too great here, so I don't think the flaw is in the calculation. Just apply average speed for uniform acceleration: (v i+v f)/2=s/t. The way you are computing acceleration is very sensitive to any error you have in your time measurements.Īs I'm sure you realize, there's no need to go via acceleration at all. *my teacher said that I should be getting a negative value for change of energy and she hasn't taught us how to do include experimental errors.she said the errors shouldn't affect the results like that so there must be something wrong with my process, but I can't figure out what it is? Please help.įinal energy (3 trials) calculated by (mv^2)/2ġ) 0.26 J (it's greater that EI but should not be!) Potential energy is zero and there's only kinetic energy, and also final energy should be smaller than initial energy because of friction, but I keep getting a greater value for all of them, as well as my change in mechanical energy, which should be negative and I keep getting a positive value. Then when I move to solve the total energy at the bottom of the ramp, there is a problem. Then, I used the vf = vi + a(t) to find the velocity at the bottom of the ramp.Īnd then I found the total energy at the top of the ramp, which would only be the potential energy as initial velocity is zero. So then I used the d = vi*t + (a(t)^2)/2 formula to calculate the acceleration of the block and I got I did 3 trials of letting the block slide down the ramp and the time intervals I got each are: The hypotenuse of the ramp is 63 cm and the height is 36 cm. A block of 55 g is sliding down a ramp of 35 degrees of inclination.
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