In fighting forest fires, airplanes work in support of ground crews by dropping water on the fires. A pilot is practicing by dropping a canister of red dye, hoping to hit a target on the ground below.

If the plane is flying in a horizontal path at an altitude of 83.0 m above the ground and with a speed of 67.0 m/s , at what horizontal distance from the target should the pilot release the canister? Ignore air resistance.

Take free fall acceleration to be g .

I have attached the solution to the question as a picture below.

MY QUESTION is WHY IS THE DISTANCE (83M) negative when the person answers the question?

When I try to solve the question using positive value for 83, I get undefined number. Can someone tell me the physics reasoning why we take -83m.

Thanks.

Consider the vertical and horizontal distances separately. Vertical: You know: vO (= 0), Ay (= -83 m), a (= -9.8 m/s2) You want: t Use: Ay = v0.t + 1/2.a.t2 = 1/2.a.t2 t = V(2.Ay / a) = V(2(-83)/(-9.8)) = 4.11 s Horizontal: V = Ax /t Ax = v.t Ax = (67.0)(4.1) =274.7 m