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1. The figure below shows a \"conical pendulum\", in which the bob (the small ob

ID: 1415953 • Letter: 1

Question

1. The figure below shows a "conical pendulum", in which the bob (the small object at the lower end of the cord) moves in a horizontal circle at constant speed. (The cord sweeps out a cone as the bob rotates.) The bob has a mass of 0.050 kg, the string has length L = 0.50 m and negligible mass, and the bob follows a circular path of circumference 0.88 m. (a) What is the tension in the string? N (b) What is the period of the motion? s

2. A sphere of mass 3.3 10-4 kg is suspended from a cord. A steady horizontal breeze pushes the sphere so that the cord makes a constant angle of 39° with the vertical. (a) Find the magnitude of that push. N (b) Find the tension in the cord. 26.18 . N

Explanation / Answer


1)


circumference s = 2*pi*R = 0.88

radius R = 0.88/(2*pi) = 0.14


sintheta = R/L


theta = 16.3

along vertical


T*costheta = mg


T*sin16.3 = 0.05*9.8


T = 1.75 N <<<<<<<<<<---------answer

along horizantal


T*sintheta = mv^2/R


v = 2*pi*R/T = 0.88/T

T*sintheta1.75*sin16.3 = 0.05*4*pi^2*R/T^2


1.75*sin16.3 = 0.05*4*pi^2*0.14/T^2


T = 0.75 s   <<<<<<<<<<---------answer

+++++++++++++++++


++++++++++++++++++++++

2)


along vertical


T*costheta = mg

T*sintheta = F

tantheta = F/mb

tan39 = F/(3.3*10^-4*9.8)


T = 26.18*10^-4 N <<<<<<<<<<---------answer

T*cos39 = 3.3*10^-4*9.8

T = 41.6*10^-4 N     <<<<<<<<<<<<<<<---------answer