Expert: Paul Klarreich - 3/19/2009

Question
Bill Nye The science guy launched a kiwi fruit straight into the air. The kiwi fruit took off at a height of 4 meters at a speed of 75 meters per second. Answer the following questions using the above information.
A) How long was it until the kiwi fruit landed on the ground?
B) What was the maximum height the kiwi fruit achieved?
C) How long did it take the kiwi fruit to reach maximum heights?
D) After 3 seconds what was the height of the kiwi fruit?

Answer
Questioner:   Dakota
Country:  United States
Category:  Advanced Math
Private:  No
 
Subject:  algebra II height equation
Question:  Bill Nye The science guy launched a kiwi fruit straight into the air. The kiwi fruit took off at a height of 4 meters at a speed of 75 meters per second. Answer the following questions using the above information.
A) How long was it until the kiwi fruit landed on the ground?
B) What was the maximum height the kiwi fruit achieved?
C) How long did it take the kiwi fruit to reach maximum heights?
D) After 3 seconds what was the height of the kiwi fruit?
...............................................
The usual equation is:

h = -16 t^2 + v0 t + h0, where

v0 is the initial velocity.
h0 is the initial height,
and 'initial' means 'at t = 0'.

A) How long was it until the kiwi fruit landed on the ground?

>> 'on the ground' means h = 0.
>> 'How long was it' means 'find t'
C) How long did it take the kiwi fruit to reach maximum heights?

>> (do this before B)
How do you find the vertex of a parabola?  Use what you have learned about quadratic equations.

B) What was the maximum height the kiwi fruit achieved?

Use the answer to C.

D) After 3 seconds what was the height of the kiwi fruit?

>> 'After 3 seconds' means 'at t = 3'.

Now see what you can do.  Let me know if and where you got stuck.