mechanics question (1 Viewer)

[aDimitri]

Patel exercise 9C, question 4. Looking for a worked solution.
Thanks in advance

A model plane of mass 5kg attached to the end of an inelastic wire of length 20m flies in a horizontal circle of elevation 30°, while the other end of the wire is held fixed. If the lift (force) L acts at right angles to the wire and L is twice the weight of the plane, find:
a) the speed of the plane in m/s
b) the tension in the wire in newtons.

 

[braintic]

Solution here:

View attachment Patel Exercise 9C Q4.pdf

Let me know whether that matches your answers.

 

[obliviousninja]

Solution here:

View attachment 30599

Let me know whether that matches your answers.

This.

 

[Kurosaki]

Solution here:

View attachment 30599

Let me know whether that matches your answers.

That looks right (Patel says to take g as 9.8 m/s^2 which should explain the slight discrepancy).

 

[aDimitri]

Ah holy crap i realised where I went wrong. I had R = 10, rather than R = 10sqrt(3). I hate stupid shit like that. Thanks very much for the nicely typed solution, braintic