query 4

course phy 201

assignment #004004. `Query 4

Physics I

02-08-2008

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22:51:17

Intro Prob 6 given init vel, accel, `dt find final vel, dist

If initial velocity is v0, acceleration is a and time interval is `dt, then in symbols what are the final velocity vf and the displacement `ds?

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RESPONSE -->

v0=0

a=a

'dt='dt

vAve=(vf+v0)/2

vAve='ds/'dt

aAve='dv/'dt

confidence assessment: 0

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22:52:29

**You would use accel. and `dt to find `dv:

a * `dt = `dv. Adding `dv to initial vel. vo you get final vel.

Then average initial vel. and final vel. to get ave. vel.:

(v0 + vf) / 2 = ave. vel.

You would then multiply ave. vel. and `dt together to get the distance.

For example if a = 3 m/s^2, `dt = 5 s and v0 = 3 m/s:

3 m/s^2 * 5 s = 15 m/s = `dv

15 m/s + 3 m/s = 18 m/s = fin. vel.

(18 m/s + 3 m/s) / 2 = 10.5 m/s = vAve

10.5 m/s * 5 s = 52.5 m = dist.

In more abbreviated form:

a * `dt = `dv

v0 + `dv = vf

(vf + v0) /2 = vAve

vAve * `dt = `ds so

`ds = (vf + v0) / 2 * `dt.

**

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RESPONSE -->

i wasn't sure if this is what you were going for or not, i definatly didnt put mine in order.

self critique assessment: 1

I believe you understand. Let me know if you don't.

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22:57:53

What is the displacement `ds associated with uniform acceleration from velocity v0 to velocity vf in clock time `dt?

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RESPONSE -->

you use the change in position to determine the average velocity 'ds/'dt. which is used to determine the average acceleration.'dv/'dt. and vf+v0/2 is how you find the average velcoity. vf-v0 gives us the change in velcity.

confidence assessment: 0

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22:59:03

** Since accel is uniform vAve = (v0 + vf) / 2.

Thus displacement is

`ds = vAve * `dt = (v0 + vf) / 2 * `dt,

which is the first equation of uniformly accelerated motion. **

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RESPONSE -->

cool

self critique assessment: 1

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23:00:30

Describe the flow diagram we obtain for the situation in which we know v0, vf and `dt.

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RESPONSE -->

is this the parabola equation?

where the constant acceleration is double th eacceleration of the quardraic position function.

confidence assessment: 0

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23:01:18

02-08-2008 23:01:18

Query Add any surprises or insights you experienced as a result of this assignment.

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NOTES ------->

** The first level in the diagram would contain `dt, v0 and vf.

Then v0 and vf would connect to `dv in the second level.

The second level would also contain vAve, connected from vf in the first level to v0 in the first level.

The third level would contain an a, connected to `dv in the second level and `dt in the first level.

The third level would also contain `ds, connected to vAve in the fourth level and `dt in the first level. **

Query Add any surprises or insights you experienced as a result of this assignment.

thats it

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Good work. See my notes and let me know if you have questions. &#