Using this graph or otherwise,
Find the velocity with which and the time at which the front of the train passed B
The distance traveled can be obtained from the area of the time-velocity graph. As we know when the train passes the post it will travel 100m in 10s. In the graph this region is a trapezoid and its area will be 100.
Area of trapezoid `= (11+V)/2xx10`
`(11+V)/2xx10 = 100`
`V = 9`
So the velocity of train at the start of post is 9m/s.
Using gradient of the graph we can say;
`V/T = 11/(T+10)`
`9/T = 11/(T+10)`
`T = 45s`
So the front of train will pass B after 45 seconds it started travel and with a velocity of 9m/s.