A metal bar 70 cm long and 4.00 kg in mass is supported on two knife-edges placed 10 cm from each end. A 6.00 kg load is suspended at 30 cm from one end. Find the reactions at the knife edges. (Assume the bar to be of uniform cross section and homogeneous.) (a) R = 64.88 N R = 33.12 N (c) R = 43.12 N R = 43.12 N (b) R = 54.88 N R = 43.12 N (d) R, = 33.12 N R = 33.12 N