A uniform bridge span weighs 70.0 × 10³ N and is 40.0 m long.An automobile weighing 15.0 × 10³ N is parked with its center of gravity located 12.0 m from the right pier.What upward support force does the right pier provide? A) 24.5 × 10³ N B) 35.5 × 10³ N C) 65.0 × 10³ N D) 45.5 × 10³ N

Question

Quizplus · Accepted Answer

The total torque about the left pier must be zero for equilibrium. The torque due to the bridge's weight acts at its center (20 m from the left pier), and the torque due to the car acts 28 m from the left pier. Solving for the right pier's force gives 45.5 × 10³ N.

A Uniform Bridge Span Weighs 70