The top portion of a pole saw used to trim small branches from trees is shown in the figure part (a). The cutting blade BCD [see figure parts (a) and (c)] applies a force P at point D. Ignore the effect of the weak return spring attached to the cutting blade below B. Use properties and dimensions given in the figure.
(a) Find the force P on the cutting blade at D if the tension force in the rope is T 25 lb (see free body diagram in part (b)].
(b) Find force in the pin at C.
(c) Find average shear stress τave and bearing stress σb in the support pin at C [see Section a-a through cutting blade in figure part (c)].

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Rope, tension 1 Weak return spring 2T Saw blade Collar Cutting a blade (a) Top part of pole saw Cutting blade 27 500 BC 6 in. (tin.) 32 20° 6 in. C Collar s 1 in P 20 in Pin at C 70° in (b) Free-body diagram (c) Section a-a