Part A:
See Ch2 Sheet 21 which describes the travel of the ball launched upward and then back to the level of the students hand. What is the only acceleration present ? Is this acceleration the same at any given time of the travel ?
Part B:
See Sheet 22. After the ball A, launched upward, has reached the students hand again, what is its velocity at that point, magnitude and direction, compared to the initial velocity when ball B is launched downward ?
What do you conclude then about the velocities of ball A and B when they reach the ground ?
6 comments:
For part b of this problem....How is the final velocity the same? Unless there is a terminal velocity reached before it hit the ground...the ball that was thrown downward should have a higher final velocity...Even though it does have the same acceleration due to gravitational forces...It's initial velocity is negative already, while the ball thrown upward was positive...?
I agree,
If you throw one ball up in the air, then throw another ball directly at the ground. The ball that was thrown into the air has a longer distance to the ground, therefore more time for the acceleration of gravity to effect it while its in freefall?
Right?
i thought that you could use the formula 2.5 v=g x t found on page 19 of chapter 2 notes.
if it takes more time for the first ball that was thrown upward to reach the ground then the velocity would have to be greater....
This is a really bad question, good thing we have infinite attempts so we can reflect on why this is so bad.
The Professor is hoping we think about the key term; "Terminal Velocity".
But the thing is the problem says "A building", then it goes on to list a variable of H for height.
So we could be standing on a 1 story building, where Terminal velocity will never be achieved, or a 200 story building.
Too general of a problem, not enough information to tell how tall of building we were on.
Very bad.
Re all up to 9/6 10:48 am:
Have you all tried to answer the question in the start of the blog after "See Sheet 22" ? Make the height of the tossing hand equal to the "bottom", the launch point on Sheet 22. Sheet 22 tells you how the velocity of the ball after having fallen back to the height of the launch relates to the launch velocity (magnitude and direction). How do the initial conditions for the ball after fall back and the ball tossed downward compare ?
Re 9/6 10:48 am:
"Terminal" velocity is a constant velocity at which the ball would arrive after traversing a large distance due to gravity and friction in the air cancelling each other. Do we, using g=9.81, consider friction or do we neglect it ?
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