Sorry for so many questions, just coming back here after going through all the review questions I could get. Here we go:(adsbygoogle = window.adsbygoogle || []).push({});

A cowboy wants to open a saloon door with a revolver shot. The swinging door (Mass M, width b) is hit on the very edge and the bullet (Mass m, velocity v) lodges into the door.

a) Derive an expression for the moment of inertia of the door. - I got this to be J = Mb^2/3, and not too worried about this question.

b) Derive an expression for the angular velocity w, with which the door swings open after being hit. -I'm supposed to use the conservation of angular moment here, right? I ended up getting w = 3mv/((M+m)b^2), but I don't think this is right.

c) How many degrees will the door open at most, with D* as the "angular benchmark"? Use the numbers M = 10 kg, b = .6 m, m = 10 g, v = 500 m/s, D* = 1.2 Nm. - I don't even know if "angular benchmark" is the right translation for D* (it's Winkelrichtgroesse in German if that helps anyone). We were also given the formula Moment of Force = -D*phi. Am I going to want to plug the info I'm given into the formula I created in b?

Thank you again.

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# Homework Help: Angular Momentum -Opening a door with a bullet

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