Question

Samantha threw and apple out of the window fr the tenth floor of her apartment building. The equation y= -16t^2 +120 can be used to represent the fruits height above the ground, where t represents time, in seconds, after she threw the apple. How long did it take the apple to hit the ground? Round to the nearest hundredth.

Answer 1

Answer:
time taken = 2.74 seconds

Explanation:
We are given that:
y = -16t² + 120 models the situation where:
y is the floor number
t is the time taken for the apple to hit the ground

We are also given that the floor number (y) is 10. Therefore, all we have to do is substitute with y in the above equation and solve for the time t as follows:
y = -16t² + 120
10 = -16t² + 120
120 - 10 = 16t² 
110 = 16t²
t² = 110/16
t = ±√6.875
either t = 2.74 seconds ..........> accepted
or t = -2.74 seconds .........> rejected as time cannot be in negative

Hope this helps :)