#$&*
Phy 201
Your 'cq_1_08.2' report has been received. Scroll down through the document to see any comments I might have inserted, and my final comment at the end.
** **
A ball is tossed upward at 15 meters / second from a height of 12 meters above the ground. Assume a uniform downward acceleration of 10 m/s^2 (an approximation within 2% of the 9.8 m/s^2 acceleration of gravity).
• How high does it rise and how long does it take to get to its highest point?
answer/question/discussion: ->->->->->->->->->->->-> :
(vf-v0)^2/2a
(0-15m/s)^2/2(10)=225/20= 11.25 m
We add this to the 12 meters to get a height of 23.25 m.
vAve= (vf+v0)/2--- (we use 0 for vf because the ball will have no velocity when it turns to come back down.)
so, (0+15m/s)/2= 7.5 m/s
vAve= ‘ds/ ‘dt
7.5m/s= 23.25m/ ‘dt
7.5 ‘dt= 23. 25m
‘dt=3.1 seconds to reach the highest point.
#$&*
• 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: ->->->->->->->->->->->-> :
10m/s/s= (vf-0)/6.2= 62m/s was the final velocity when it hit the ground
It will strike the ground 6.2 seconds after it was tossed.
#$&*
• At what clock time(s) will the speed of the ball be 5 meters / second?
answer/question/discussion: ->->->->->->->->->->->-> :
If the change in velocity is 15m/s (15-0). We can then find the ‘dt of the average velocity by using the equation: vAve= ‘dv/ ‘dt
5m/s= 15/ ‘dt
5 ‘dt= 15
‘dt= 3 seconds
At 3 seconds it will reach 5m/s
#$&*
• At what clock time(s) will the ball be 20 meters above the ground?
7.5m/s =20m/ ‘dt
7.5m/s ‘dt= 20m
2.67 s= ‘dt
• How high will it be at the end of the sixth second?
answer/question/discussion: ->->->->->->->->->->->-> :
The ball will be back on the ground at this point.
#$&*
I am unsure how to do some of these questions, but expect to learn during these assignments. I understand the formulas for acceleration and velocity and the corresponding formulas, but when gravity is thrown in I get a little lost.
** **
30 minutes
** **
You do need a revision on this one. You're on the right track, just need to get the details.
&#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. &#