# Basketball player shooting ball, finding velocity for a no backboard shot

BlazdNConfusd

## Homework Statement

An h1 = 2.13 m tall basketball player wants to make a basket from a distance d = 10.8 m, as seen in the figure.

If he shoots the ball at α = 47.2° angle, at what initial speed must he throw the basketball so that it goes through the hoop without striking the backboard? The height of the basketball hoop is h2 = 3.05 m.

## Homework Equations

1/2((gd^2)/((cos(theta)^2 * ((H1-H2) +(d * tan(theta))) = Vo^2

## The Attempt at a Solution

I have absolutely no idea how to use that equation. I was horrible and dropped my trig class and in doing so completely forgot how to use equations with theta. Any help is greatly appreciated.

BlazdNConfusd
any ideas anybody? ive literally been working on this for hours

Staff Emeritus
Homework Helper
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## Homework Equations

1/2((gd^2)/((cos(theta)^2 * ((H1-H2) +(d * tan(theta))) = Vo^2
I'm not sure where that equation comes from, but (for now) will trust that it leads to the correct solution.

Make sure your calculator is in degrees mode (not radians), and calculate the following:

cos of 47.2 = ____?
tan of 47.2 = ____?

Then you can just plug those numbers in for cos(theta) and tan(theta).

On a TI 83+ calculator:

Select "degrees" mode:

MODE button
On 3rd line, put cursor on "Degree"
ENTER button -- "Degree" should be highlighted
2nd QUIT button

Calculate cosine of 47.2 degrees:

COS button
47.2
")" button
ENTER button

Hope that helps.