A concrete highway is built of slabs 12 m long (at 15◦ C). How wide should the expansion cracks between the slabs be (at 15◦ C) to prevent buckling of the range of temperature is -30◦ C to +50◦ C?

Shafts are machine elements that are used to a) carry axial loads b) direct shear loads c) transmit power d) rotate at constant speed e) none of the above circular and square shafts subjected to the same torque under the same circum behave a) the same way b) almost the same way