Answer:
d) 105 s
Step-by-step explanation:
Given the following data;
Distance A (length of train) = 100 m
Velocity = 72 km/h to meters per seconds = 72 * 1000)/3600 = 72000/3600 = 20 m/s
To find the time;
Time = distance/speed
Time = 100/20
Time = 5 seconds.
II. When the distance (bridge) is 2km;
Distance B = 2km = 2*1000 = 2000 meters
Time = distance/speed
Time = 2000/20
Time = 100 seconds
Therefore, total time = 5 + 100 = 105 seconds