A solid round shaft (Sut=295 MPa), 20mm in diameter, has a groove 3mm-deep. It is subjected to a purely reversing torque of 180 Nm. If the endurance limit is 105.3 MPa. Using f=0.9, calculate the following: 116. The constant a in fatigue strength equation. a. 2.80 b. 826.4 117. The constant b in fatigue strength equation. a. 0.134 b. 0.149 118. The number of cycles a. 30,200 cycles b. 22,300 cycles c. 2.52 d. 669.4 C. -0.1339 d. -0.150 c. 23,300 cycles d. 32,000 cycles