Answer: Time interval of camera film him is [tex]1\leq t\leq \sqrt{2}[/tex]
Step-by-step explanation:
Given: A stuntman jumping off a 20-m-high building is modeled by the equation [tex]h=20-5t^2[/tex], where t is the time in seconds..........(1)
Height of camera to film stunt man is between 15 m and 10 m.
To find interval of time the camera film him, substitute h=15m in (1),we get
[tex]15=20-5t^2\\\Rightarrow-5=-5t^2\\\Rightarrow\ t^2=1\\\Rightarrow\ t=1\text}[time is always positive]{[/tex]
Now, substitute h=10m in (1),we get
[tex]10=20-5t^2\\\Rightarrow-10=-5t^2\\\Rightarrow\ t^2=2\\\Rightarrow\ t=\sqrt{2}\text}[time is always positive]{[/tex]
[tex]\Rightarrow1\leq t\leq \sqrt{2}[/tex]
Therefore ,time interval of camera film him is [tex]1\leq t\leq \sqrt{2}[/tex]
