Question

The height of a stuntperson jumping off a building that is 20 m high is modeled by the equation h = 20 -57, where t is the time

in seconds. A high-speed camera is ready to film the person between 15 m and 10 m above the ground. For which interval of
time should the camera film the person?
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Answer 1

B

Explanation:

took the unit test

Answer 2

A stuntman jumping off a 20-m-high building is modeled by the equation h = 20 – 5t2, where t is the time in seconds. A high-speed camera is ready to film him between 15 m and 10 m above the ground. For which interval of time should the camera film him?

Answer:

`1\leq t\geq √(2)`

Explanation:

Given:

A stuntman jumping off a 20-m-high building is modeled by the equation

`h =20-5t^(2)`-----------(1)

A high-speed camera is ready to making film between 15 m and 10 m above the ground

when the stuntman is 15m above the ground.

height
`h = 15m`

Put height value in equation 1

`15 =20-5t^(2)`

`5t^(2) =20-15`

`5t^(2) =5`

`t^(2) =1`

`t =\pm1`

We know that the time is always positive, therefore
`t=1`

when the stuntman is 10m above the ground.

height
`h = 10m`

Put height value in equation 1

`10 =20-5t^(2)`

`5t^(2) =20-10`

`5t^(2) =10`

`t^(2) =(10)/(5)`

`t^(2) =2`

`t=\pm√(2)`

`t=√(2)`

Therefore ,time interval of camera film him is
`1\leq t\geq √(2)`