Forces exerted on bridges

Flash Animation by Mark Cowan
ePhysics, UCLA

Clicking on stop, in the above animation, will allow you to drag the truck in order to view the forces exerted on the truck when the truck is at specific locations on the bridge. Click on "show second truck", in the above animation, in order to view the forces exerted on the pillars when a second truck crosses the bridge. You will also be able to drag the second truck when you click on stop.

Single Truck
  1. The truck(s) in our animation has a mass of 2100 kg. Is that a large or small mass for a truck?
  2. How can we determine the forces exerted on the pillars of the bridge?
  3. What are the forces on each of the pillars when the truck is a distance of 30 meters from the left pillar? What are the forces on each of the pillars when the truck is a distance of 60 meters from the left pillar?
  4. What are the forces on each of the pillars when the truck is a distance of 40 meters from the right pillar? What are the forces on each of the pillars when the truck is a distance of 90 meters from the right pillar?
Two Trucks
  1. What is the maximum force that can be exerted on either of the two pillars when two trucks are crossing the bridge? Assume that the mass of each truck is 2100 kg.
  2. How can we determine the forces exerted on the pillars of the bridge when two trucks are crossing the bridge?
  3. What are the forces on each of the pillars when the first truck is a distance of 30 meters from the left pillar while the second truck is a distance of 90 meters from the left pillar? What are the forces on each of the pillars when the first truck is a distance of 60 meters from the left pillar while the second truck is a distance of 70 meters from the left pillar?
  4. What are the forces on each of the pillars when the first truck is a distance of 60 meters from the right pillar while the second truck is a distance of 30 meters from the right pillar? What are the forces on each of the pillars when the first truck is a distance of 20 meters from the right pillar while the second truck is a distance of 40 meters from the right pillar?
  5. What are the forces on each of the pillars when the first truck is a distance of 70 meters from the right pillar while the second truck is a distance of 30 meters from the left pillar? What are the forces on each of the pillars when the first truck is a distance of 60 meters from the right pillar while the second truck is a distance of 90 meters from the left pillar?