Assn4Query

course Phy 201

Would like to have feedback. Thanks, Joshua

ۂ ¡z½֯dGassignment #004

004. `Query 4

Physics I

06-30-2008

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20:53:53

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 -->

a * 'dt = 'dv

'dv + v0 = vf

(v0+vf) = vAve

vAve * 'dt = ds

confidence assessment: 3

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20:53:57

06-30-2008 20:53:57

**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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20:56:16

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

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RESPONSE -->

acceleration = vAve

'ds = vAve*'dt

confidence assessment: 3

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20:56:27

06-30-2008 20:56:27

** 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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21:03:19

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

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RESPONSE -->

a first box would contain 'dt, v0 and vf

on a second layer v0 and vf would connect to a box containing 'dv

a third layer a would be in a box connect to the 'dv box and to the 'dt box.

next would be 'ds which is connected to 'dt and vAve. vAve should be on a previous level connected to v0 and vf

confidence assessment: 1

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21:03:57

06-30-2008 21:03:57

** 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. **

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21:04:35

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

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RESPONSE -->

A little confusing at times but over all informational

confidence assessment: 3

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21:04:41

06-30-2008 21:04:41

** Student Response: I think I really confused what information stood for what in the Force and Pendulum Experiment. However, I enjoy doing the flow diagrams. They make you think in a different way than you are used to. INSTRUCTOR NOTE: These diagrams are valuable for most people. Not all--it depends on learning style--but most. **

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Your work looks good. Let me know if you have any questions. &#