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

An astronaut in space cannot use a scale or balance to weigh objects because there is no gravity. but she does have devices to measure distance and time accurately. she knows her own mass is 77.4 kg , but she is unsure of the mass of a large gas canister in the airless rocket. when this canister is approaching her at 3.50 m/s , she pushes against it, which slows it down to 1.30 m/s (but does not reverse it) and gives her a speed of 2.60 m/s . what is the mass of the canister?