PHY 201
Your 'cq_1_08.2' 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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A ball is tossed upward at 15 meters / second from a height of 12 meters above the ground. Assume a uniform downward acceleration of 10 m/s^2 (an approximation within 2% of the 9.8 m/s^2 acceleration of gravity).
• How high does it rise and how long does it take to get to its highest point?
answer/question/discussion: ->->->->->->->->->->->-> :
If the initial velocity is 15 m/s then I can subtract it from the acceleration and multiply it by the time interval, and hopefully get a zero, because that would be the top or the highest point. I am going to use the equation: v = v0 + ag * time = 15 m/s – 10 m/s^2 * 1.5 s = 0 m/s. So, it takes 1.5 seconds to reach the highest point.
Then, if the initial velocity is 15 m/s and the final velocity is 0 m/s, then I can calculate the average velocity and the displacement as well. The average velocity is: (15 m/s + 0 m/s) / 2 = 7.5 m/s , 7.5 m/s * 1.5 s = 11.25 meters. So, the ball would travel at distance of 11.25 meters to the highest point.
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• How fast is it then going when it hits the ground, and how long after the initial toss does it first strike the ground?
answer/question/discussion: ->->->->->->->->->->->-> :
I can get the velocity of the speed at 15 m/s starting point, but I am not sure how to calculate the velocity under that when it hits the ground.
Check the explanation at the link. You'll understand.
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• At what clock time(s) will the speed of the ball be 5 meters / second?
answer/question/discussion: ->->->->->->->->->->->-> :
1 second, because the initial velocity subtracted from the acceleration and multiplied by a time interval will give you the 5 m/s, so 1 second was the answer: 15 m/s – 10 m/s/s * 1 = 5 m/s
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• At what clock time(s) will the ball be 20 meters above the ground?
• How high will it be at the end of the sixth second?
answer/question/discussion: ->->->->->->->->->->->-> :
I am not sure that I am doing this correctly, because it just does not make since to me.
You would have `ds = 20 m, a = 10 m/s^2, v0 = 15 m/s. Be sure you see that, give it a try with that information, then check the link.
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45 minutes
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&#See any notes I might have inserted into your document. If there are no notes, this does not mean that your solution is completely correct.
Then please compare your solutions with the expanded discussion at the link
Solution
Self-critique your solutions, if this is necessary, according to the usual criteria. Insert any revisions, questions, etc. into a copy of this posted document. Mark any insertions with &&&& so they can be easily identified.If your solution is completely consistent with the given solution, you need do nothing further with this problem. &#