Answer:
s = height above ground
s = 60 + 20 t - 4.9 t^2 (standard physics equation on earth)
at t = 0
s = 60 (clearly :)
now when does it hit the bleak earth?
That is when s = 0
4.9 t^2 - 20 t -60 = 0
solve quadratic and use the positive t (the negative t was back before you threw it if you had thrown it from the ground)
t = 6.09 or - 2.01
use t = 6.09
now to do the last part there are two obvious ways to get t at the peak
1. look for vertex of parabola
2. look for halfway between t = -2.01 and t = 6.09
I will do it the hard (11) waay by completing the square
4.9 t^2 - 20 t = -(s-60)
t^2 - 4.08 t = -.204 s + 12.2
t^2 - 4.08 t +2.04^2 = -.204 s +12.2 + 4.16
(t-2.04)^2 = -.204(s-80.2)
so
top at 80.2 meters at t = 2.04 s
===============
quick check on time
should be average of 6.09 and -2.01
=4.08 /2 = 2.04 check
- 9 and - 3
consider 3 units to the left and right of - 6
- 6 - 3 = - 9 ( 3 units to the left of - 6 )
- 6 + 3 = - 3 ( 3 units to the right of - 6 )
The answer would be A!
Whenever there is a fraction in the exponent, the numerator is under the square root, and the denominator is on the outside of the square root!
Additionally, since the negative is outside of the square toot, then it also outside of the parenthesis.
I believe the answer is (0,0)
