1. The problem statement, all variables and given/known data
A bridge of length 60 m and mass 51800 kg is supported at each end. A truck of mass 45000 kg is located 26 m from the left end.

2. Relevant equations
What is the force on the bridge at the left point of support?

3. The attempt at a solution

I know your supposed to use the sum of the forces equals zero. Then the sum of the torques equal zero, but i can't get the right answer!!

 PhysOrg.com science news on PhysOrg.com >> Heat-related deaths in Manhattan projected to rise>> Dire outlook despite global warming 'pause': study>> Sea level influenced tropical climate during the last ice age
 the reason is because you are trying to set the sum of all forces equal to zero when you don't even know enough forces. Look at torques. Try my suggestion on the other problem.

Mentor
Blog Entries: 1
 Quote by kitty9035 I know your supposed to use the sum of the forces equals zero. Then the sum of the torques equal zero, but i can't get the right answer!!
First identify all the forces acting on the bridge. Then show us exactly how you calculated the torques. (What point did you use as your pivot point?)