Question

a. A uniform beam of mass 20 kg and length L is supported horizontally by a hinge at the wall and a metal wire at the far end. The wire can support a maximum of 840 N. The wire makes a 60 degree angle with the wall where it attaches. A 40 kg mass is placed on the beam. How far away from the wall can the mass be placed without breaking the wire? (The moment of inertia about the center of mass for a beam is 1/12 ML^2 and about one end is 1/3 ML^2)

b. A uniform beam of mass 20 kg and length 13 m is supported horizontally by a hinge at the wall and a metal wire at the far end. A 40 kg mass is moved slowly outward until the wire breaks when the mass is 5.2 m away from the wall. What is the initial magnitude of the angular acceleration of the beam when the string breaks? (The moment of inertia about the center of mass for a beam is 1/12 ML^2 and about one end is 1/3 ML^2)

Answer 1

The initial angular acceleration is 1.18 rad/s²