A fire helicopter carries a 640 kg bucket of water at the end of a 20.0 m long cable. Flying back from a fire at a constant speed of 40.0 m/s, the cable makes an angle of 42.0° with respect to the vertical. Determine the force exerted by air resistance on the bucket.

Answer 1

Draw a free body diagram for the bucket.

The cable tension force is T
T cos 42 = bucket weight (which you know)
T sin 42 = air resistance force

Divide the second equation by the first. Remember that sin/cos = tan, for any angle.

tan 42 = (air resistance force)/weight

Solve for the unknown force