course phy 201
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19:04:16 Video Clip 7: Slope triangle, instantaneous acceleration, tangent line How do we represent the calculation of the rate which velocity changes on graph of velocity vs. time?
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RESPONSE --> You would use slope triangle. the hypotnus extends from on point on the line to another and then we find the slope of the line.
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19:04:31 ** Correct response from student: We can represent the rate of velocity change by calculating the slope. Slope is rise/run which is change in velocity/change in time **
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RESPONSE --> right
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19:05:44 If we know the velocity at every clock time, that how we find the precise rate at which velocity changes adding given clock time?
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RESPONSE --> The question is worded wrong! I'm not sure what I am even suppose to do
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19:07:26 ** STUDENT RESPONSE: I am not sure I understand, however I think you would make a triangle between the two times and velocities--i.e., between the two points on the v vs. t graph. Then find slope. INSTRUCTOR CRIQITUE: You would do this, but you would calculate the rate or slope over smaller and smaller intervals containing the clock time at the specified instant. You would try to determine the limiting value as the interval approaches 0. This limiting value is the instantaneous rate as well as the slope of the tangent line. **
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RESPONSE --> So, I guess you would find the slope over a lot of spots on the graph that are very small and then you would be able to atleast give an answer that was in the midlle of the guess
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19:10:15 How do we depict the instantaneous rate of velocity change on a graph of velocity vs. time?
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RESPONSE --> Keep taking smaller intervals for the slope and then you will see the slope change.
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19:10:52 ** See the preceding answer. **
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RESPONSE --> The limiting value is the instantaneous rate as well as the slope of the tangent line.
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19:14:47 Physics video clips 08: Finding displacement: define displacement, then calculate by common sense, by formula, by area What is the difference between displacement and distance?
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RESPONSE --> displacement is the change in position. distance can not be negative it can only be positive while displacement can be positive or negative. Displacement is the change in velocity multiply by the change in time. 'ds = vAve*'dt.... the average velocity time the change in time is the area.
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19:14:56 ** Displacement tells the change in position, which is the same as distance but displacement can have a negative or positive value whereas distance is always positive. **
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RESPONSE --> right
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19:15:56 How do we calculate displacement from velocity and time interval? What is the common sense of this calculation?
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RESPONSE --> The displacement is calculated by ds=vAve*'dt This is also how you would calculate the area aswell
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19:16:04 ** Correct response from student: The vAve multiplied by the time interval. If the vAve tells us how far it travels one second, then if we multiply it by the time interval it will tell us how far it will travel in that amt. of time. **
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RESPONSE --> right
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19:16:36 How do we use a graph to help visualize the calculation of displacement when velocity is constant?
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RESPONSE --> by the area under is the acutal area of the information which is vAve * 'dt
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19:16:54 ** Since the vel. is constant, a graph of velocity vs. clock time over a given time interval will form a rectangle whose 'height' represents the velocity and whose width represents the time interval. Multiplying velocity * time interval gives displacement. A graph of position vs. clock time will be a straight-line graph, and the displacement corresponding to two clock times will be the change in the y coordinate between those clock times. **
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RESPONSE --> right
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19:17:32 What aspect of a v vs. t graph tells us the displacement?
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RESPONSE --> ?
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19:17:47 ** The area of the rectangle formed between the two given clock times will indicate the displacement (see preceding comment). **
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RESPONSE --> right that is what i said before.
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