A passenger on a train traveling 90km/h on a straight, level track notes that it takes another train (180 m long and moving with constant velocity) 4.0s to pass by. What is the velocity of that passing train relative to the ground?
**please include explanation** thnx!!
The relative velocity is the distance divided by the time.
Now subtract the train moving 90km/hr, and you have the other train velocity.
Watch units.
so:
V = 180 m / 4 s = 45 m/s
convert to km/h
V = 162 km/h
This is the velocity relative to the first train, which is moving 90 km/h relative to the ground.
Then V = 162 + 90 km/h = 252 km/h
That's pretty fast...:-P
To find the velocity of the passing train relative to the ground, we need to consider the velocity of the passenger train and the time it takes for the passing train to go by.
First, let's convert the length of the passing train from meters to kilometers. There are 1000 meters in one kilometer, so the length of the passing train is 0.180 km.
Next, we need to convert the time taken for the passing train to go by from seconds to hours since the velocity of the passenger train is given in km/h. There are 3600 seconds in one hour, so the time taken is 4.0s/3600s/h = 0.00111 h.
Now, let's consider the relative velocity of the passing train with respect to the passenger train. The relative velocity can be calculated by dividing the distance traveled by the time taken. Since the distance traveled is the sum of the lengths of both trains (0.180 km + 0 km), and the time taken is 0.00111 h, the relative velocity is (0.180 km + 0 km) / 0.00111 h = 162.16 km/h.
Finally, to find the velocity of the passing train relative to the ground, we can subtract the velocity of the passenger train from the relative velocity. Since the passenger train is traveling at 90 km/h and the relative velocity is 162.16 km/h, the velocity of the passing train relative to the ground is 162.16 km/h - 90 km/h = 72.16 km/h.
Therefore, the velocity of the passing train relative to the ground is 72.16 km/h.