Posted by NeedHelp on Wednesday, April 4, 2012 at 4:24pm.
The height(h) of an object that has been dropped or thrown in the air is given by: h(t)=4.9t^2+vt+h
t=time in seconds(s)
v=initial velocity in meters per second (m/s)
h=initial height in meters(m)
A ball is thrown vertically upwardd from the top of the Leaning Tower of Pisa (height=53m) with an initial velocity of 30m/s. Find the time(s) at which:
a) the ball's height equals the hight of the tower
b) the ball's height is greater than the height of the tower
c) the ball's height is less than the height of the tower
d)the ball reaches its maximum height
I don't know how to do this problem.
Please Help and Thank You very much =)

Math  Steve, Wednesday, April 4, 2012 at 4:39pm
heck, they gave you the equation.
h(t) = 4.9t^2 + 30t + 53
a) ball goes up, comes back down to the top of the tower. So, we want
53 = 4.9t^2 + 30t + 53
0 = 4.9t^2 + 30t
0 = t(4.9t + 30)
so, t=0 (at the start) or t = 6.12 (as it comes back down)
b) same calculation but, t is between 0 and 6.12. That is 0 < t < 6.12
c) same calculation, but restricting t to positive values, t>6.12
Naturally, we could also restrict t to the point where height >= 0.
d) vertex of any parabola is where x = b/2a = 30/9.8 = 3.06
h(3.06) = 98.9

Math  Anonymous, Wednesday, April 4, 2012 at 5:08pm
I don't get how you got:
vertex of any parabola is where x = b/2a = 30/9.8 = 3.06
h(3.06) = 98.9
where did all the numbers come from?

Math  Anonymous, Wednesday, April 4, 2012 at 5:35pm
how did you get t=6.12 for a)???
Answer This Question
Related Questions
 Math  The height(H) of an object that has been dropped or thrown in the air is ...
 Math Help (URGENT X10)  This is really urgent so please please please help. The...
 Algebra  The height, in meters, of a projectile can be modeled by h= 4.9t^2 + ...
 College algebra  When a ball is thrown up into the air, it makes the shape of a...
 Algebra 1  A ball is thrown upward with an initial velocity of 35 meters per ...
 Math  In physics, one learns that the height of an object thrown upward from an...
 math  A ball is thrown upward with an initial velocity of 35 meters per second ...
 Maths  object thrown upward from an initial height of h0 feet with an initial ...
 algebra  A ball is thrown upward with an initial velocity of 14 meters per ...
 Algebra  THe function h(t)=16t^2+v0t+h0 describes the height in feet above the...
More Related Questions