Ph1 Query 1

course Phy 121

6/13 at 1:50pm

Question: `qExplain in your own words how the standard deviation of a set of numbers is calculated.

*********************************************

Your solution: It is the square root of the “average” squared. The term average here is the number of items divided by 1 less than there really is.

Confidence Assessment: Not to confident, its not the easiest set of calculations to remember and it seems that I did all the math on my calculator and can not refer to it.

*********************************************

Question: Explain in your own words the process of fitting a straight line to a graph of y vs. x data, and briefly discuss the nature of the uncertainties encountered in the process. For example, you might address the question of how two different people, given the same graph, might obtain different results for the slope and the vertical intercept.

*********************************************

Your solution: To find a best fit line, take a piece of string and connect it between the highest and lowest X coordinate points. To find the Y intercept from this, extend the string until it intercepts the Y axis. Discrepancies may be seen here due to the fact that one person could estimate a different point where the string passes through the Y axis, or if there isn’t a concise highest X value point, there can be variations in the average of these two coordinates.

Confidence Assessment: Pretty sure.

*********************************************

Question: Briefly state what you think velocity is and how you think it is an example of a rate.

Your solution: A speed defined in a certain direction. It is a rate since it is found with a (Change in A)/(Change in B) type equation.

Confidence Assessment: Pretty sure

.............................................

Given Solution:

A rate is a change in something divided by a change in something else.

This question concerns velocity, which is the rate of change of position: change in position divided by change in clock time. **

&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

Self-critique (if necessary):

Question: Given average speed and time interval how do you find distance moved?

*********************************************

Your solution: Make sure the speeds distance per time units are the same as the time’s unit, then multiply which crosses out the two time units leaving a distance.

Confidence Assessment: Pretty sure.

.............................................

Given Solution:

** You multiply average speed * time interval to find distance moved.

For example, 50 miles / hour * 3 hours = 150 miles. **

&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

Self-critique (if necessary):

*********************************************

Question: Given average speed and distance moved how do you find the corresponding time interval?

*********************************************

Your solution: Once again, get consistent units, but this time divide the distance by the speed which will divide out the two distance units leaving time.

Confidence Assessment: Pretty sure.

.............................................

Given Solution:

** time interval = distance / average speed. For example if we travel 100 miles at 50 mph it takes 2 hours--we divide the distance by the speed.

In symbols, if `ds = vAve * `dt then `dt = `ds/vAve.

Also note that (cm/s ) / s = cm/s^2, not sec, whereas cm / (cm/s) = cm * s / cm = s, as appropriate in a calculation of `dt. **

&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&&

Self-critique (if necessary):

Question: Given time interval and distance moved how do you get average speed?

*********************************************

Your solution: Av.Speed=Distance/Time.

Confidence Assessment: Pretty sure.

.............................................

Given Solution:

** Average speed = distance / change in clock time. This is the definition of average speed.

For example if we travel 300 miles in 5 hours we have been traveling at an average speed of 300 miles / 5 hours = 60 miles / hour. **

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