Problem 1.2 -5 A force P of 70 N is applied by Brake cable , _ = 460 mm Hand brake pivot A a rider to the front hand brake of a bicycle (P is the resultant of an evenly distributed pressure ). As the hand brake pivots at A, a tension 7 develops in the 460 -mm long brake cable (A _ 1.075 mm ?) which elongates by d = 0.214 mm . Find normal 375 mm stress s and strain - in the brake cable . P (Resultant of distributed pressure ) 50 mm -Uniform hand 100 mm brake pressure Problem 1.2-6 A bicycle rider would like to compare the effectiveness of cantilever hand brakes [see figure part (a)] versus V brakes [figure part (b)]. (a) Calculate the braking force R, at the wheel rims for each of the bicycle brake systems shown. Assume that all forces act in the plane of the figure and that cable tension 7 - 200 N. Also, what is the average compressive normal stress s on the brake pad (A - 4 cm ?)? (HINT: Because of symmetry , you only need to use the right half of each figure in your analysis .) (b) For each braking system , what is the stress in the brake cable (assume effective cross -sectional area of 1077 mm 2)