Question

MCR

Answer 1

https://gyazo.com/50eb5c92e9a52faf91e1e1dda40a92c7

Answer 2

@mathmale

Answer 3

I tried figuring it out but it can't be the answers cant be negative right?

Answer 4

This probelm has similarities to the previous one. Previously, you set the height equal to 11. This time, you set the height formula = to 0, because the height is 0 when the ball hits the ground.

Thus, you are to solve h = 0 = 255 - 21t - 16t^2.

Answer 5

What are the values of your a, b and c here?

Answer 6

a= -16t^2 b= -21t c= 255

Answer 7

Wait I think I made the 255 negative

Answer 8

Oh I changed all of their signs not just the 255

Answer 9

Actually, a=-16, not -16t^2.

What is b?

Answer 10

a, b and c are coefficients, and do NOT include the variable t.

Answer 11

b= -21 c= 255

Answer 12

Good. Now plug those values into the quadratic formula and solve for the 2 t-values.
To answer your question: When did you last hear of negative time?

Answer 13

Never :P Thats why I was confused because I got one positive and one negative answer

Answer 14

Throw out the negative answer. Yes, really.

Answer 15

Check your positive answer by subbing it into that quadratic. Is the quadratic now true?

Answer 16

Yes

Answer 17

3.39

Answer 18

If the quad. eq'n. is now true, then your answer is correct. Congrats.

Answer 19

Thanks for the help, Im not sure how many questions I have left. Can I tag you if I get stuck again? (On a different post of course)

Answer 20

Sure. But I'm not likely to stay on OpenStudy for more than a few min. longer. Happy to work with you whenever you can find me here.