SOLUTION: A ball is thrown vertically upwards from the balcony of an apartment building. The ball falls to the ground. The height of the ball , h metres, above the ground after t seconds i
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Question 140056: A ball is thrown vertically upwards from the balcony of an apartment building. The ball falls to the ground. The height of the ball , h metres, above the ground after t seconds is given by h=-5t^2 +15t +45.
What is the height of the balcony? 45m?
What is the maximum height reached by the ball?
When will the ballreach a height of 55m?
When will the ball hit the ground?
Answer by rapaljer(4671) (Show Source): You can put this solution on YOUR website!
h=-5t^2 +15t +45
Yes, the height of the building is the height at t=0, which is 45 ft.
Maximum height of the parabola occurs at
Maximum height at = seconds.
Maximum height = feet
Maximum height =
Maximum height = feet
The ball reaches 55 feet when
t=1 and t=2 seconds (at t=1 sec going up, at t=2 seconds coming down!)
The ball hits the ground when h=0.
h=-5t^2 +15t +45
0=-5t^2 +15t +45
0=-5(t^2-3t-9)
Solve this by quadratic formula, since it does not factor. The answer will contain a radical.
R^2
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