Question

A baseball is thrown vertically upward at a rate of 130 feet per second from an initial height of 4 feet. Use the projectile formula

h
=
−
16
t
2
+
v
0
t
+
h
0
to determine when the height of the ball will be 236 feet. [Recall that
v
0
is the initial velocity of the object and
h
0
is the inital height of the object.]

Answer: The baseball is at 236 feet after
2.20
Incorrect
seconds
Correct

Answer 1

-16t² + 130t + 4 = 236

-16t² + 130t - 232 = 0

8t² - 65t + 116 = 0

t = (65 ± √(65² - 4(8)(116))/16

= (65 ± √513)/16

= (65 ± 22.65)/16

= 2.65 seconds, 5.48 seconds