x
Solved

# initial velocity

Posted on 2011-03-25
Medium Priority
1,409 Views
if a person shoots a basketball overhand from a position 8 feet above the floor then the path can sometimes be modeled by the quadratic function defined by
f(x)= -16x^2/0.434v^2+1.15x+8
where v is the initial velocity of the ball in feet per second...so if the hoop is 10 feet high and 15 feet away what initial velocity does the basketball have?

- So I did what the online homework said to do and subed 15 for x and put it in the graphing calc and then put y= 10 in the graph calc and found the intersect...which is 0.044 but I can not for the life of me get the velocity

Totally feel like I am missing something critical.
Any help is appreciated.
``````Removed "Computer Servers" from the Zones.

rindi,
EE ZA Storage
``````
0
Question by:MaxDes101
• 3
• 2

LVL 14

Expert Comment

ID: 35217734
You need to replace your hard drive
0

LVL 33

Expert Comment

ID: 35219116
>> y = f(x)= -16  x²/0.434v² + 1.15x + 8

Any idea where this formula comes from?  I didn't try to derive the formula, but I'll accept it as a given, since I gather it is part of the problem. I guess buried in it are things like the angle at which the shooter throws the ball.

Did you miss a set of parenthesis. Do you think the formula is actually:
>> y = f(x)= -16  x²/(0.434v²) + 1.15x + 8

>> I did what the online homework said to do and subed 15 for x ... put y= 10

So, is this what you did?

10 =  -16 (15)²/(0.434v²) + 1.15(15) + 8

All I see here are numbers and v² which is solvable.
0

LVL 27

Expert Comment

ID: 35219404
Your equation is a mess
but given that there maybe dimensions  hidden in the constants and the it is a very special equation ,note that at x = 15 f(x) should be 10 because the ball should be at the height of the basket. putting x = 15 and f(x) = 10 the only unknown in your equation is v. solve for v.
0

LVL 33

Expert Comment

ID: 35219562
>> putting x = 15 and f(x) = 10 the only unknown in your equation is v. solve for v.
I thought I did that:
>> 10 =  -16 (15)²/(0.434v²) + 1.15(15) + 8
0

LVL 27

Expert Comment

ID: 35219904
"I thought I did that"
indeed you did
0

LVL 33

Accepted Solution

phoffric earned 2000 total points
ID: 35223583
In case you are interested in the origins of your formula, take a look at this:
http://hyperphysics.phy-astr.gsu.edu/hbase/traj.html#tra8

Notice that y = y(x) has only two terms. Your formula has three terms. The last term in your formula is +8, which is the height of the ball (i.e., 8 feet above the floor - must be a tall shooter).

That is, f(0) = 8 for your formula. But the formula in the link is showing an intial height of 0 (i.e., f(0) = 0), so that term is left out in the link.
0

## Featured Post

Question has a verified solution.

Are you are experiencing a similar issue? Get a personalized answer when you ask a related question.

Have a better answer? Share it in a comment.

## Join & Write a Comment Already a member? Login.

Aerodynamic noise is the cause of the majority of the noise produced by helicopters. The inordinate amount of noise helicopters produce is a major problem in the both a military and civilian setting. To remedy this problem the use of an aerogel coat…
There's never been a better time to become a computer scientist. Employment growth in the field is expected to reach 22% overall by 2020, and if you want to get in on the action, it’s a good idea to think about at least minoring in computer science …
Finds all prime numbers in a range requested and places them in a public primes() array. I've demostrated a template size of 30 (2 * 3 * 5) but larger templates can be built such 210  (2 * 3 * 5 * 7) or 2310  (2 * 3 * 5 * 7 * 11). The larger templa…
I've attached the XLSM Excel spreadsheet I used in the video and also text files containing the macros used below. https://filedb.experts-exchange.com/incoming/2017/03_w12/1151775/Permutations.txt https://filedb.experts-exchange.com/incoming/201…
###### Suggested Courses
Course of the Month11 days, 6 hours left to enroll

#### 601 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.