Shear and moment: two identical 20-mm thick plates are bolted to the top and bottom flange to form the built-up beam.
a) if the beam is subjected to a shear force of v = 250 kn, determine the allowable maximum spacing s of the bolts to the nearest mm. assume each bolt has a shear capacity of 30 kn, and i = 307.5e-6 m4 .
b) what is the mp (plastic moment) of the beam assuming bolts can take infinite shear and y = 250 mpa

Simon is writing a story about an astronaut whose spacecraft has been boarded by space pirates. the astronaut has her lucky penny in her hand behind her back as the space pirates break into the control room. she has just locked the controls so that the ship is accelerating in the direction of the control room’s ceiling. simon wants the astronaut to use the penny to hit a button on the control panel to turn off the lights and escape. the button is located a short distance behind and below the astronaut’s hands. how should simon use the theory of relativity to describe what the astronaut must do in order to hit the button?