b) Determine the minimum crack size that can be tolerated in a sheet of high-tensile yield stress of 1200 MPa and a toughness 30 kJ/m2. If the design stress safety factor is 1.5. Assume that E for the material is 210 GPA.

Acentrifuge in a medical laboratory rotates at an angular speed of 3,700 rev/min. when switched off, it rotates through 54.0 revolutions before coming to rest. find the constant angular acceleration (in rad/s2) of the centrifuge. your response is within 10% of the correct value. this may be due to roundoff error, or you could have a mistake in your calculation. carry out all intermediate results to at least four-digit accuracy to minimize roundoff error. rad/s2