cq_1_011

Phy 121

Your 'cq_1_01.1' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.

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The problem:

Here is the definition of rate of change of one quantity with respect to

another:

The average rate of change of A with respect to B on an interval is

*average rate of change of A with respect to B=(change in A) /(change in B)

Apply the above definition of average rate of change of A with respect to

B to each of the following. Be sure to identify the quantity A, the

quantity B and the requested average rate.

*If the position of a ball rolling along a track changes from 10 cm to 20 cm

while the clock time changes from 4 seconds to 9 seconds, what is the

average rate of change of its position with respect to clock time during this

interval?

answer/question/discussion:

###average rate of change of A with respect to B=(change in A) /(change in B)

A = ds (20cm - 10cm ) = 10 cm

B = dt (9/sec - 4/sec) = 5/sec

dt = vAve / dt

2 cm /sec = 10cm / 5 sec

*If the velocity of a ball rolling along a track changes from 10 cm / second

to 40 cm / second during an interval during which the clock time changes

by 3 seconds, then what is the average rate of change of its velocity with

respect to clock time during this interval?

answer/question/discussion:

###average rate of change of A with respect to B=(change in A) /(change in B)

A = vAve (40cm - 10cm ) = 30 cm

B = dt = 3/sec

dv = vAve / dt

10 cm /sec = 30cm / 3 sec

*If the average rate at which position changes with respect to clock time

is 5 cm / second, and if the clock time changes by 10 seconds, by how

much does the position change?

answer/question/discussion:

###average rate of change of A with respect to B=(change in A) /(change in B)

A = ds = 5 cm/sec

B = dt = 10 sec

vAve = ds * dt

50cm = 5 cm/sec * 10 sec

*You will be expected hereafter to know and apply, in a variety of

contexts, the definition given in this question. You need to know this

definition word for word. If you try to apply the definition without using

all the words it is going to cost you time and it will very likely diminish

your performance. Briefly explain how you will ensure that you remember

this definition.

answer/question/discussion:

By copying the definition to a notepad for referance.

*

You are asked in this exercise to apply the definition, and given a

general procedure for doing so. Briefly outline the procedure for applying

this definition, and briefly explain how you will remember to apply this

procedure.

dt = time

ds = speed

vAve = distance

dv = velosity increse

A description of the procedure should start with the definition.

`dt is time interval, i.e., the change in clock time t

`ds is displacement, the change in the position s

vAve is the average value of the velocity v

`dv is the change in velocity (note that velocity doesn't always increase; if we refer to 'change in' then we allow for increase or decrease)

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30 min

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Good work, but be sure to see my note after your last response..