Solve Work & Angle Homework: Plane Towing Glider & Water Skier

[songoku]

Homework Statement

1. A small plane tows a glider at constant speed and altitude. If the plane does 2.00 x 10⁵ J of work to tow the glider 145 m and the tension in the tow rope is 2560 N, what is the angle between the tow rope and the horizontal?

2. Water skiers often ride to one side of the center line of a boat as shown below. In this case, the ski boat is traveling at 15 m/s and the tension in the rope is 75 N. If the boat does 3500 J of work on the skier in 50.0 m, what is the angle θ between the tow rope and the center line of the boat?

Homework Equations

W = F d cos θ
W = Δ KE

The Attempt at a Solution

1.
W = F d cos θ
2 x 10⁵ = 2560 x 145 cos θ
θ = 57.4^o
I'm not sure because I don't know the picture of plane tows a glider. I am only using the formula

2.
W = F d cos θ
3500 = 75 x 50 cos θ
θ = 21.04^o
Is the speed given in the question not important?

Thanks

 

[TSny]

All looks good to me. The speed is irrelevant in part b.

 

[CWatters]

and me. Speed irrelevant in both parts as the problem is the same.

Speed information would have be needed had the question given you "power" rather than "work".

 

[songoku]

All looks good to me. The speed is irrelevant in part b.

and me. Speed irrelevant in both parts as the problem is the same.

Speed information would have be needed had the question given you "power" rather than "work".

Thanks