SOLUTION: Solve step by step. 18. A tennis ball is launched straight upward with an initial velocity of 24.5 m/s from the edge of a cliff that is 117.6 meters above the ground. Which

Question 1155163: Solve step by step.
18. A tennis ball is launched straight upward with an initial velocity of 24.5 m/s from the edge of a cliff that is 117.6 meters above the ground. Which quadratic equation could be used to correctly determine when the ball will hit the ground:

4.9t^2 + 24.5t + 117.6 = 0
-4.9t^2 - 24.5t + 117.6 = 0
-4.9t^2 + 24.5t - 117.6 = 0
4.9t^2 + 24.5t - 117.6 = 0
-4.9t^2 + 24.5t + 117.6 = 0
19. Solve the equation you chose in question 18 to determine when the ball will hit the ground. (HINT: If you don't get one of the answers listed for this question, then maybe you chose the wrong equation in #18. Use this opportunity to double check your work!)

t = 8 seconds
t = 4 seconds
t = 3 seconds
t = -3 seconds
The ball will never reach the ground.

20. Using the same equation, determine when the ball is at a height of 49 meters.
Answer by ewatrrr(24785) (Show Source): You can put this solution on YOUR website!



Hi  

18.       4.9t2 + 24.5t - 117.6 = 0

19.           t = (-24.5 +( 24.5^2 + 4x4.9x117.6)^0.5)/ 9.8

               t = 3 seconds.

20.          4.9t2 + 24.5t - 49 = 0

              t = (-24.5 +( 24.5^2 + 4x4.9x 49 )^0.5)/ 9.8



 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=1560.65 is greater than zero. That means that there are two solutions: .

  

    

    

    

    Quadratic expression  can be factored:

  

  Again, the answer is: 1.53112887414928, -6.53112887414928.
Here's your graph:



 

RELATED QUESTIONS

A tennis ball is launched straight upward with an initial velocity of 24.5 m/s from the... (answered by Edwin McCravy)
A tennis ball is thrown vertically upward with an initial velocity of +6.9 m/s.
What... (answered by richard1234)
Please help me fix these 
 
My teachers response:
4.  You had it in your 3rd step.... (answered by josgarithmetic)
A ball is thrown with an initial upward velocity of 5 m/s. What is its velocity after 1.5  (answered by ikleyn,solver91311)
Solve.

a ball is thrown upward from the roof of a building 100 m tall with an initial... (answered by GSems22,bucky)
Help please! I'm so confused by this problem. Can you explain it step by step?

if an... (answered by josmiceli)
Show work please

10.    Work backwards to write a quadratic equation that will have  (answered by josgarithmetic)
A tennis ball is thrown vertically upward with
an initial velocity of +7.4 m/s.
What... (answered by Alan3354)
Word Problem Help

A ball is thrown from an initial height of 4 feet with an initial... (answered by MathLover1)