A hot-air balloon has just lifted off and is rising at the constant rate of 2.0m/s. Suddenly one of the passengers realizes she has left her camera on the ground. A friend picks it up and tosses it straight upward with an initial speed of 12m/s. If the passenger is 2.5m above her friend when the camera is tossed, how high is she when the camera reaches her?

Respuesta :

Answer:3.085 m ,5.914 m

Explanation:

Given

Velocity of hot air balloon(v)=2 m/s

Velocity at which camera is thrown up(u)=12 m/s

at t=0 passenger is at 2.5 m above

Let say it takes t sec for camera to reach balloon and balloon has traveled a distance of x m in that time

x=2t

also for camera

[tex]2.5+x=12\times t-\frac{1}{2}gt^2[/tex]------1

substitute value of x in 1

[tex]2.5+2t=12t-5t^2[/tex]

[tex]5t^2-10t+2.5=0[/tex]

[tex]t^2-2t+0.5=0[/tex]

[tex]2t^2-4t+1=0[/tex]

[tex]t=\frac{4\pm \sqrt{8}}{4}=\frac{2\pm \sqrt{2}}{2}[/tex]

so there are two instances when both heights are equal

for [tex]t=\frac{2-\sqrt{2}}{2}[/tex]

[tex]x=2\times \frac{2-\sqrt{2}}{2}[/tex]

[tex]x=2-\sqrt{2}=0.5857 m[/tex]

Therefore balloon is at a height of 2.5+0.5857=3.085 m

For [tex]t=\frac{2+\sqrt{2}}{2}[/tex]

[tex]x=2+\sqrt{2}[/tex]

balloon at a height of 5.914 m