2. Analysis: Because Xiao Fang stood motionless by the railway, the distance the train passed by her was the conductor. It is easy to know the speed of the train. Multiply the speed of the train by the 6 minutes to cross the bridge, and you can get the sum of the length of the train and the length of the bridge. Subtract the length of the bus and you get the length of the bridge.

Solution: 360 ÷ 2× 6-360 = 180× 6-360

= 1080-360

=720 (meters).

This bridge is 720 meters long.

3. Let the train be x meters long and y meters per second.

(1260+X)/60= speed Y=(20 10+X)/90.

The solution is X=240 Y=25.

Because when a train passes through a tunnel or a bridge, the calculation of the passing time starts from the moment when the locomotive enters the tunnel head to the moment when the train leaves at the rear. In other words, the distance the train passes through the tunnel plus its own length.

4. Analysis: Assuming that the original speed passes through the 162m railway bridge, the train takes 16×2=32 (seconds), thus turning the problem into one similar to that in Example 3.

Solution: What is the original speed of the train

(162-82) ÷ (32-22) = 8 (m ∕ s),

The length of the train is

8× 22-82 = 94 (meters).

A: The train speed is 8m/s and the length is 94m.

5. Analysis: Take the length of the team as the "captain" and find out the "captain" first. Because each column has 346÷2= 173 (people) and the distance from front to back is 1m, the length of the whole team is1x (173-1) =172. After finding out the "captain", we can find out the time to cross the bridge.

Solution:/kloc-0 /× (346 ÷ 2-1) =172 (m),

(702+ 172) ÷ 23 = 38 (point).

A: It takes 38 minutes for the whole team to get on the bridge and leave.

6. 1, first calculate the train speed180 ÷12 =15m/s.

2. Calculate the relative speed of trucks and trains168 ÷ 6 = 28m/s.

3. The truck and the train are in relative motion, so the relative speed = the difference between them, so the truck speed = the relative speed-the train speed = 28-15 =13m/s.