Expert: Paul Klarreich - 10/8/2009

Question
QUESTION: what are the equations that you need to solve a parabola?

and my trig question....

A satellite traveling in a circular orbit 1600km above the surface of earth takes 2 hours to make an orbit. The radius of the earth is 6400km.
a) fine the linear speed of the satellite.
b) find the distance the satellite travels in 4.5 hours.
i know that the equation for linear speed is v= s/t and that
2(pie) comes in somewhere.


ANSWER: Questioner: dillon
Country: United States
Category: Advanced Math
Private: No
Subject: basic alegbra and trig
Question: what are the equations that you need to solve a parabola?

and my trig question....

A satellite traveling in a circular orbit 1600km above the surface of earth takes 2 hours to make an orbit. The radius of the earth is 6400km.
a) fine the linear speed of the satellite.
b) find the distance the satellite travels in 4.5 hours.
i know that the equation for linear speed is v= s/t and that
2(pie) comes in somewhere.
...............................
Hi, Dillon,

Your first question is meaningless.  There is no such thing as 'solve a parabola'.  Reread the definitions, use the vocabulary correctly, and you will increase your understanding.

For the second:

The 'circular orbit' is a circle with its center as the center of the Earth.  Its radius is the 6400 + 1600 = 8000 km.

So:
1. Find the circumference. (look up the formula.)
2. That is the 'length' of the orbit.  (your 's')
3. Divide by time = 2 hours.  
4. That gives your 'v' in km/h.

Now you can finish up.


---------- FOLLOW-UP ----------

QUESTION: yeah, i guess you can't really solve a parabola. i meant how do you find the vertex for parabolas.

Answer
QUESTION: yeah, i guess you can't really solve a parabola. i meant how do you find the vertex for parabolas.


If  y = f(x) = ax^2 + bx + c   is the equation for the parabola, then
         -b
1) Find x = --------
         2a

2) Find  y = f(that), by substitution.