A community for students.

Here's the question you clicked on:

55 members online
  • 0 replying
  • 0 viewing

anonymous

  • 4 years ago

A cannonball is fired into the air. It's height, h, in metres after t seconds is given by the relation: h=-4.6 (t-7.5)^2+285 a) what is the maximum height reached by the cannon and what time is this reached. b) what was the initial height of the cannon? c) what is the height of the cannon after 10.5 seconds? d) how long is the cannon in the air?

  • This Question is Closed
  1. mathmate
    • 4 years ago
    Best Response
    You've already chosen the best response.
    Medals 0

    Do you just want just the answer or wnat to know how to find it?

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

    Can you show me how to find it please with the ans

  3. y2o2
    • 4 years ago
    Best Response
    You've already chosen the best response.
    Medals 2

    h = -4.6t²+69 t+26.25 the vertex of this function is the the time of maximum height time of maximum height = -b/2a = 7.5 maximum height = -4.6(7.5)²+69(7.5)+26.25 = 285 meters 2) initial height (t = 0) = 26.25 meters 3) after 10.5 sec. (t = 10) = 243.6 meters 4) time in air (h = 0) t = 15.37

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

    y do u put h as zero?

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

    im confused.

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

    can yu show us what yu plugged in for 4)

  7. y2o2
    • 4 years ago
    Best Response
    You've already chosen the best response.
    Medals 2

    this ball will reach a maximum heigh (h) then it returns back the same height (-h) so it's total value = 0

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

    oohhh i get it

  9. y2o2
    • 4 years ago
    Best Response
    You've already chosen the best response.
    Medals 2

    BTW..this will be from the position of projection , not the surface of the cannon

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

    The answer to part a is already given in the way the formula is expressed: h=-4.6(t-7.5)^2+285 is in the vertex form. It shows that the vertex (highest or lowest point) is at the position (7.5,285), or a height of 285 after 7.5 seconds.

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

    can yu put the equation where yu hav to isolste it so we kno wht to rite

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

    or put in our calculator

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

    isolate "t"

  14. y2o2
    • 4 years ago
    Best Response
    You've already chosen the best response.
    Medals 2

    actually I can't find anything confusing here is the problem with expanding of the brackets ?!

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

    no i jus dun understand how to solve 4)

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

    like how do u isolate "t" to find the time?

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

    ...

  18. y2o2
    • 4 years ago
    Best Response
    You've already chosen the best response.
    Medals 2

    did you understand why h = 0 ?!!!

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

    yeah we understand that, we just dont get how to put the "t" on one side of the equation, and the rest on the other side of the equation

  20. y2o2
    • 4 years ago
    Best Response
    You've already chosen the best response.
    Medals 2

    well, as h = 0 then h = -4.6 (t-7.5)²+285 = 0 -4.6 (t-7.5)² = -285 [divide by -4.6] (t-7.5)² = 61.95 [approx.] t-7 = 8 or t-7 = -8 [by taking +ve and -ve square root] t = 15 or t = -1 [refused answer bec. t is never -ve]

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

    thank you :D charmi - u get it now? :P

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

    yupp

  23. y2o2
    • 4 years ago
    Best Response
    You've already chosen the best response.
    Medals 2

    I'm glad you understood :)

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

    ty

  25. 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.