# Determining Drag Coefficient

A fire helicopter carries a 560-kg bucket at the end of a cable 20.6 m long as in the figure below. As the helicopter flies to a fire at a constant speed of 39.2 m/s ,the cable makes an angle of 39.6 with respect to the vertical. The bucket presents a cross-sectional area of $$3.96m^2$$ in a plane perpendicular to the air moving past it. Determine the drag coefficient, assuming that the resistive force is proportional to the square of the bucket's speed.

I've got that $$C_d = 2mg / (V_T)^2A\rho$$, but I don't know how to find the terminal velocity of the bucket to find the coefficient of drag. Can anyone help?

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NateTG
Homework Helper
You don't need to use the terminal verlocity at all, but a more general expression for the force of friction. You have enough information to determine the force of friction, and you know the airspeed.

But the equation for the force of friction is $$f_f = \mu N$$. I don't know the coefficent of friction.... unless it's 1 since it's flying through the air?

Pyrrhus
Homework Helper
Remember Newton's 1st Law!

$$\sum F_{x} = 0$$

$$\sum F_{y} =0$$

NateTG
$$F_{drag} = \frac{C_{D}}{A} \frac{\rho v^2}{2}$$