Question

After 1 second, the ball is 121 feet in the air; after 2 seconds, it is 224 feet in the air.Find the height, in feet, of the ball after 3 seconds in the air.

Answer 1

The height, in feet, of the ball after 3 seconds in the air = 309

Explanation:

We have
`s = ut +(1)/(2)at^2`

After 1 second, the ball is 121 feet in the air

Here s = 121 ft , t = 1 s

`121=u* 1-(1)/(2)* a* 1^2\\\\2u-a=242`

After 2 seconds, it is 224 feet in the air

Here s = 224 ft , t = 2 s

`224=u* 2-(1)/(2)* a* 2^2\\\\u-a=112`

Subtracting two equations

2u-a-(u-a)=242-112

u = 130 ft/s

130 - a = 112

a = 18 ft/s²

When t = 3s

`s=130* 3-(1)/(2)* 18* 3^2=309ft`

The height, in feet, of the ball after 3 seconds in the air = 309