a football is thrown into the air. the height, h(t), in metres, after t seconds is modelled by h(t) = -4.9(t-1.25)^2 + 9. how high off the ground was the ball when it was thrown? please explain!

Question

baldymcgee6 · Answer

The height it was thrown from is going to correspond to the y intercept.

baldymcgee6 · Answer

If you logically think about it, at what time is the ball going to be thrown at?

anonymous · Answer

i suck at math omg idk

baldymcgee6 · Answer

Don't get frustrated, just think. The ball is going to be released at t=0, the time doesnt start until the ball is released.

anonymous · Answer

so do i have to replace the t with something?

baldymcgee6 · Answer

Good, you're starting to think on the right track. What do you think you need to replace t with?

anonymous · Answer

if i replace it with 0 will that make sense..

baldymcgee6 · Answer

It makes sense to me ;) does it makes sense to you?

anonymous · Answer

ya so is that the right answer :)

baldymcgee6 · Answer

That is not your answer yet, when you input a t (time sec) into this function, what will it output?

anonymous · Answer

doesnt it already have a t..

baldymcgee6 · Answer

Yes, but when you input a t value, say t=0, what will the function output?

anonymous · Answer

the time it was thrown?

baldymcgee6 · Answer

When you input t=0 into the function, it will output the corresponding height.
h(0) = -4.9(0-1.25)^2 + 9

anonymous · Answer

ohhhhhhhh

baldymcgee6 · Answer

So how high will the ball be at t=0 seconds?

anonymous · Answer

do i just solve for h?

baldymcgee6 · Answer

Yes, well, h is already isolated, so just solve the right side of  h(t) = -4.9(t-1.25)^2 + 9

baldymcgee6 · Answer

and substitute 0 in for t

anonymous · Answer

OMG thank you! you saved my life! i have a test tomorrow and i was struggggling with that question

baldymcgee6 · Answer

Feel free to give out a "best response" and leave a testimonial. :) What did you get for the height at t=0?

anonymous · Answer

1.34 and i willl !

baldymcgee6 · Answer

Right on! are you allowed to use a graphing calculator, if so, I can show you a trick!

anonymous · Answer

yess we are

baldymcgee6 · Answer

Do you use a ti 83 or 84?

anonymous · Answer

no idk how

baldymcgee6 · Answer

okay, maybe we will leave that for another time! :) good luck on the test!

anonymous · Answer

lol thats okay this is easy enough! thanks again! you're awesome :)