Thursday, June 23, 2011

Unit 4


Today, we wrapped up unit three and moved on to unit four: 2D kinematics. A "solve for one variable" type of kinematic equation quickly turned into a more complicated multi-step process. This unit made understanding physics much harder.
We learned to set up a 2D kinematics equation with a T graph. (Shown below.) Some of the most important things to remember are to separate x axis things from y axis things (vegas rule) and time is a value of y (aYer).
If I were to dive off a diving board 5 meters above the ground, going forward at 1.5 m/s, how far would I be from the bottom of the diving board to the place I landed?

___x___|___y___
     ?m    d    5m     (height of diving board)
 0 m/s/s  a  -9m/s/s(gravity)
              t
1.5 m/s  v              (given)
1.5 m/s  vo  0 m/s   (given)

Now I have to solve for time using d=1/2at^2+Vot
5=1/2(-9.8)(t^2)+(0)(t)
1.02=t^2
1.01s = t
This means it took 1.01 seconds for me to hit the water.

The next step is to solve for distance of x using d=1/2at^2+Vot
d=1/2(0)(1.01)^2+(1.5)(1.01)
d=(1.5)(1.01)
d= 1.515 m

My horizontal range is 1.515 meters.

5 comments:

  1. I really liked your post. It went over a lot of what we learned and showed the work along the way. Good job!

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  2. Good job, but please make sure that your units in your t-chart are correct. You will need to correct your acceleration units to be m/s/s.

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  3. Pretty sweet that you used diving at a higher level that poolside, this is kind of like those cliff of impending death problems we did. Also nice drawing and t chart.

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