The discussion revolves around a problem related to centripetal force, specifically focusing on the calculation of an angle in a physics context. Participants are examining the relationship between tension, gravitational force, and centripetal force in the setup described in the problem statement.
Multiple participants have arrived at the same angle of 52 degrees, while the mark scheme suggests a different angle of 36 degrees. There is ongoing exploration of the assumptions made regarding mass and its relevance to the problem, with some participants suggesting that the mass may not be necessary for the calculation.
Participants note discrepancies in the mass values used in the problem and express concerns about the clarity of the question's requirements. There is also mention of the potential oversight in the problem's setup regarding the lift generated by the plane.
I did that and I got 52 degrees as my answer. The mark scheme says 36 but I'm not too sure if they used the correct value for mass.tommyxu3 said:Maybe you can write down your way to find the angle?
You use the information you gave to get ##\tan \theta?##
Banker said:I did that and I got 52 degrees as my answer. The mark scheme says 36 but I'm not too sure if they used the correct value for mass.
F = mrw^2PeroK said:You will need to show your working for people to help you properly. You haven't said at all how you use the angular velocity, for example.
Banker said:F = mrw^2
F = 0.2(0.35)(6)^2
Central force = 2.5 N
Let Tension = T and the angle theta = x
From the diagram, Tcosx = mg
Tsinx = central force
hence Tsinx = 2.5
Dividing the first eq by the second:
Tsinx/Tcosx = 2.5/mg
Simplifying gives tanx = 2.5/mg
Weight, mg, = 0.2 x 9.8 (0.2kg is the mass of the plane)
hence tanx = 1.28
x = 52 degrees.
Ahh thank you for the clarification! Yeah the Scottish qualifications board are subpar compared their English counterparts.PeroK said:You're correct. You can see in the solution that they put ##0.35## for the mass. The funny thing is that the answer is independent of the mass of the plane! There was never any need to use the mass. I guess even the people who set these questions don't like algebra!
I can't believe that!Banker said:Ahh thank you for the clarification! Yeah the Scottish qualifications board are subpar compared their English counterparts.
It's worse than that. For part b they used the centripetal force calculated in part a. In part a, the correct mass was used, but in part b they got confused between the mass number, 0.2, and the radius number, 0.35. So in their calculation the masses did not cancel, which is why they got the wrong answer for the angle.PeroK said:You're correct. You can see in the solution that they put ##0.35## for the mass. The funny thing is that the answer is independent of the mass of the plane! There was never any need to use the mass. I guess even the people who set these questions don't like algebra!