A community for students.

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

anonymous

  • 4 years ago

If a ball is thrown vertically upward from the roof of 64 foot building with a velocity of 16 ft/sec, its height after t seconds is s(t)=64+16t−16t2. a) What is the maximum height the ball reaches? b) What is the velocity of the ball when it hits the ground (height 0)?

  • This Question is Closed
  1. lalaly
    • 4 years ago
    Best Response
    You've already chosen the best response.
    Medals 2

    Set the derivative of the equation equal to zero to find the maximum height ds/dt = 16-32t= 0 t = 16/32 = .5 seconds substitute that in the equation s=64+16(0.5)-16(0.5)^2

  2. lalaly
    • 4 years ago
    Best Response
    You've already chosen the best response.
    Medals 2

    to find part b you set s(t)=0 then solve the quadratic equation to get two values of t ignore the negative one, then u know that V(t) is derivative of s(t) so u find the derivative and substitute the time u get, to find the velocity

  3. anonymous
    • 4 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    i dont understand how i should go about solving b

  4. lalaly
    • 4 years ago
    Best Response
    You've already chosen the best response.
    Medals 2

    first set s(t) =0 so u have 64+16t−16t^2=0 now solve this quadratic equations u will get two solutions for t

  5. anonymous
    • 4 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    so i got 2.5 as the positive solution

  6. lalaly
    • 4 years ago
    Best Response
    You've already chosen the best response.
    Medals 2

    u should get 7.5 and -0.5 are u sure u did it right?

  7. anonymous
    • 4 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    guess not

  8. lalaly
    • 4 years ago
    Best Response
    You've already chosen the best response.
    Medals 2

    \[t=\frac{-16 \pm \sqrt{16^2-4(-16)(64)}}{2(-16)}\]

  9. lalaly
    • 4 years ago
    Best Response
    You've already chosen the best response.
    Medals 2

    re check ur calculations

  10. lalaly
    • 4 years ago
    Best Response
    You've already chosen the best response.
    Medals 2

    your positive solution will be 7.5 so usualy if u say s(t) is the displacement the derivative of that is the velocity and the derivative of velocity is acceleration but here we only need the velocity so take the derivative of s(t) V=ds/dt=16-32t now substitute the t=7.5 in the above equation u will get V=16-32(7.5) And the answer is the velocity u need

  11. anonymous
    • 4 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    ive got -224

  12. lalaly
    • 4 years ago
    Best Response
    You've already chosen the best response.
    Medals 2

    yeah u got it right

  13. Not the answer you are looking for?
    Search for more explanations.

    • Attachments:

Ask your own question

Sign Up
Find more explanations on OpenStudy
Privacy Policy

Your question is ready. Sign up for free to start getting answers.

spraguer (Moderator)
5 → View Detailed Profile

is replying to Can someone tell me what button the professor is hitting...

23

  • Teamwork 19 Teammate
  • Problem Solving 19 Hero
  • You have blocked this person.
  • ✔ You're a fan Checking fan status...

Thanks for being so helpful in mathematics. If you are getting quality help, make sure you spread the word about OpenStudy.

This is the testimonial you wrote.
You haven't written a testimonial for Owlfred.