Answer:
3 seconds
Explanation:
Complete question:
An object is dropped from a bridge and allowed to freefall to the ground. The height of the object over time can be modeled using h(t)=144-16t2. How many seconds will it take the object to reach the ground? 2 seconds 3 seconds 9 seconds 16 seconds
Given the height of an object modelled by the expression;
h(t)=144-16t²
The object will reach the ground when h(t) = 0
Substitute into the formula
0 = 144 - 16t²
-144 = -16t²
144 = 16t²
Swap
16t² = 144
t² = 144/16
t² = 9
Square root both sides
√t² = ±√9
t = ±3secs
Since the time cannot be negative, hence the object will reach the ground 3 seconds after