Question

What do I have wrong in here?

A stone is thrown vertically upward at a speed of 60.0m/s.
a) How long after being thrown is it 175m above ground?

So i did -
d = V1t + 1/2at^2
175 = 60t + 1/2 (10)t^2 (rearranged and divided it all by 5)
0 = t^2 + 12t - 35
And I can't get the factors.

We were asked to consider acceleration as 10.0m/s^2

How do you know if a quadratic is a perfect square?

Answer 1

Hey, if velocity up is +, and distance up is +, then gravity down is -

Answer 2

ok so call g = 9.8 which you are calling 10 close enough DOWN

175 = 60 t - 5 t^2
t^2 - 12 t + 35 = 0
(t-5)(t-7) = 0
t = 5 and t = 7
5 seconds on the way up, 7 seconds on the way down again.