Answer:
The height of the football is 48 feet after 3 seconds
The first equation y = -16t² + 64t is the best
Step-by-step explanation:
* Lets explain how to solve the problem
- The equation of motion of an object on air without any
external force is y = ut + 1/2 at², where y is the height of the
object from the ground, u is the initial velocity, a is the
acceleration of gravity and t is the time
* Lets solve the problem
- A football is kicked at ground level with an initial velocity of
64 feet per second
∴ u = 64 feet per seconds
∵ The football is kicked upward
∴ a = -32 feet per seconds²
∵ y = ut + 1/2 at²
∴ y = 64t + 1/2 (-32)t²
∴ y = 64t - 16t²
* We will use the first equation y = -16t² + 64t
∵ y = -16t² + 64t
- We need to find the height of the football after 3 seconds
∵ t = 3 seconds
∴ y = -16(3)² + 64(3)
∴ y = 48
∵ y represents the height of the football
∴ The height of the football is 48 feet after 3 seconds
