a train 100m long is to cross a river bridge of length 800m .what time will it take to cross the bridge ? given that the train moves with a constant velocity of 36 km/h
Train is 100m long
Length of bridge is 800m
Velocity of train Is 36 km/s
Convert km/h to m/s
36km/h = 10 m/s
So, T= (800+100)/10
= 900/10
=90s
1min 70sec
To determine the time it takes for the train to cross the bridge, we need to calculate the relative speed of the train with respect to the bridge.
First, convert the velocity of the train from km/h to m/s:
Speed of the train = 36 km/h = (36 * 1000) m/ (60 * 60) s = 10 m/s
Now, let's calculate the relative speed:
Relative speed = Speed of train - Speed of bridge
The speed of the bridge is zero since it is stationary with respect to the ground.
Relative speed = 10 m/s
Next, we need to calculate the total distance that needs to be covered by the train to cross both the bridge and itself:
Total distance = Length of train + Length of bridge = 100m + 800m = 900m
Finally, we can calculate the time it takes to cross the bridge using the formula:
Time = Distance / Speed
Time = 900m / 10m/s = 90s
Therefore, it will take 90 seconds for the train to cross the bridge.