# Need help with rocket math problem

1. Aug 2, 2010

### mekias4

1. The problem statement, all variables and given/known data
A rocket is fired upward from earth with initial velocity v measured in m/s. Then maximum height in m is reached by the rocket is given by the function h(v)=Rv^2/2gR-v^2
Radius is 6.4(10^6)m and acceleration due to gravity g is 9.8m/s^2 (R and g are constants and v is the independent variable. Graph the function denoting all intercepts, asymptotes, and other points of interest.

2. Relevant equations

3. The attempt at a solution I used the escape velocity concept. I then plugged in the numbers given into the function. h(v)=6.4(10^6)(11100)^2/2(9.8)^2(6.4)(10^6)-(11100)^2
Im not sure if this is correct and how to graph with the correct axes.
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Aug 2, 2010

### eumyang

Your equation is very hard to read. Either use some more grouping symbols or retype in LaTeX.

Your equation could be read like this:
$$h(v)=\frac{Rv^2}{2gR} - v^2$$

or this:
$$h(v)=Rv^{2/2gR} - v^2$$

or this:
$$h(v)=\frac{Rv^2}{2gR-v^2}$$

and so on.

69

3. Aug 2, 2010

### mekias4

the last equation shown is what I meant...sorry

4. Aug 3, 2010

### Mandeep Deka

so where's the problems in graphing the equation?
u have the equation, h(v), take the x-axiz for v and y-axis, for h
But the graph will be a little difficult to sketch with ur hand, so u may take help of some graphing software

i couldnt get why u needed to use escape velocity concept or something. wat i see the problem, its just a single variable equation that is to be graphed.
plz clarify if i missd or misundstood something.

5. Aug 3, 2010

### mekias4

I used the escape velocity because my teacher gave us a hint using that and told me to look that up. So am I right in plugging in the numbers into the function the way i did above? Yeah I am using grapher to graph the equation. I just want to make sure I plug the correct function into the graph.