Problem 8.3 1 of 8 The mine car and its contents have a total mass of 6.9 Mg and
ID: 2040435 • Letter: P
Question
Problem 8.3 1 of 8 The mine car and its contents have a total mass of 6.9 Mg and a center of gravity at G. The coefficient of static friction between the wheels and the tracks is ?8 0.4 when the wheels are locked. The brakes at both A and B are locked. (Figure 1) Part A Find the normal force acting on the front wheels at B Express your answer to three significant figures and include the appropriate units. Value Units Submit Request Answer Part B Find the normal force acting on the rear wheels at A Express your answer to three significant figures and include the appropriate units. Figure 1 of 1 NA-1 Value Units 10kN Submit Request Answer 0.9 m Part C This question will be shown after you complete previous question(s). 0.6 m Provide FeedbackExplanation / Answer
let normal force at A be Na and normal force at Nb.
balancing forces along vertical direction:
2*(Na+Nb)=mass*g=6.9*10^6*9.8=67620000
==>Na+Nb=33810000 ..(1)
balancing total torque about A:
10*10^3*(0.9+0.15)+6.9*10^6*9.8*(1.5-0.6)=2*Nb*1.5
==>Nb=20289500 N=2.03*10^7 N
then Na=13520500 N=1.352*10^7 N