course Phy 201
I seem to be unable to access the class notes links. I click on the links in the assignment page and nothing happens. Am I missing something? Are the class notes on a CD? I'm a little confused. They've worked for me in the past, but tonight I cannot get them to work. please advise. Thanks
I don't know when you sent this, but we had a local thunderstorms in this area starting around 10 p.m. on Tuesday night and the pages were down until Wednesday morning. They should be working now.
The Class Notes are also on your CDs / DVDs.
Using the equations which govern uniformly accelerated motion determine vf, v0, a, Ds and Dt for an object which accelerates through a distance of 57.5 cm, starting from velocity 10 cm/s and accelerating at .6 cm/s/s.
Given to us is the initial velocity of 10 cm/s and the final velocity of 13 cm/s. From these we can see that the `dv is 3 cm/s. The change in position (`ds) of the object is also given to be 57.5 cm. The average velocity is found by dividing the velocities by two to give 11.5 cm/s. The vAve and the `ds are used to find the `dt: `dt=(`ds)/(vAve)=5 seconds. The only thing left to find is the average acceleration. This is simply the change in velocity divided by the change in time: 3cm/s / 5 seconds = 0.6 cm/s/s.
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Your reasoning and your results are fine.
However, just to clarify the wording, 'the equations of uniformly accelerated motion' refers to the four equations
`ds = (vf + v0) / 2
vf = v0 + a `dt
`ds = v0 `dt + .5 a `dt^2
vf^2 = v0^2 + 2 a `ds.
If you plug the given v0, vf and `ds into the appropriate equation(s), you can use these equations to get the same result.
You should be able to use the sort of direct reasoning you used here, or the equations of motion, to solve problems of this type. You should be able to do it both ways (as I'm sure is the case).