SOLUTION: A ball is thrown upward from the roof of a building 100 m tall with an initial velocity of 20 m/s. Use this information for exercises 35 to 38. When will the ball reach a he

Algebra.Com
Question 42743This question is from textbook
: A ball is thrown upward from the roof of a building 100 m tall with an initial velocity of 20 m/s. Use this information for exercises 35 to 38.


When will the ball reach a height of 80 m?
 This question is from textbook

Answer by Nate(3500)   (Show Source): You can put this solution on YOUR website!
Use General Equation:
where is the initial velocity and is the height you started at

When will the ball reach a height of 80 m?


Solved by pluggable solver: SOLVE quadratic equation with variable
Quadratic equation (in our case ) has the following solutons:



For these solutions to exist, the discriminant should not be a negative number.

First, we need to compute the discriminant : .

Discriminant d=1680 is greater than zero. That means that there are two solutions: .




Quadratic expression can be factored:

Again, the answer is: -0.65586884574495, 1.90586884574495. Here's your graph:

About 1.9 seconds ....
RELATED QUESTIONS

A ball is thrown upward from the roof of a building 100 m tall with an initial velocity... (answered by Edwin McCravy)
A ball is thrown upward from the roof of a building 100 m tall with an initial velocity... (answered by Edwin McCravy)
A ball is thrown upward from the roof of a building 100 m tall with an initial velocity... (answered by ankor@dixie-net.com,Earlsdon)
A ball is thrown upward from the roof of a building 100 m tall with an initial velocity... (answered by ankor@dixie-net.com)
a ball is thrown upward from the roof of a building 100 m tall with an initial velocity... (answered by ankor@dixie-net.com)
A ball is thrown upward from the roof of a building 100 m tall with an initial velocity... (answered by ankor@dixie-net.com)
A ball is thrown upward from the roof of a building 100 m tall with an initial velocity... (answered by MathLover1,solver91311)
Solve. a ball is thrown upward from the roof of a building 100 m tall with an initial... (answered by GSems22,bucky)
A ball is thrown upward from the roof of a building 100m tall with an initial velocity of (answered by scott8148)