Physics
posted by Bob
A train 500 m long is moving on a straight track with a speed of 84.2 km/h. The engineer applies the brakes at a crossing, and later the last car passes the crossing with a speed of 16.4 km/h. Assuming constant acceleration, determine how long the train blocked the crossing.Disregard the width of the crossing.

Damon
distance engineer moved = 500 m = .5 km
average speed = (84.2 +16.4)/2 = 50.3
km/hr
(during constant acceleration you can use the average of first and last for the distance and time)
time = distance/speed = .5km / 50.3 km/hr
= .00994 hours
* 3600 = 35.8 seconds
Respond to this Question
Similar Questions

Physics
When a high speed passenger train travelling at 161km/h rounds a bend,the engineer is shocked to see that a locomtive has improperly entered onto track from a siding and is a distance D=676m ahead.The locomotive is moving at 29km/h. … 
Physics
An engineer in a locomotive sees a car stuck on the track at a railroad crossing in front of the train. When the engineer first sees the car, the locomotive is 210 m from the crossing and its speed is 26 m/s. If the engineerâ€™s reaction … 
physics
The engineer of a passenger train traveling at 25.0 m/s sights a freight train whose caboose is 200 m ahead on the same track. The freight train is traveling at 15.0 m/s in the same direction as the passenger train. The engineer of … 
Physics doppler effect
A person standing close to a railroad crossing hears the whistle of an approaching train. He notes that the pitch of the whistle drops as the train passes by and moves away from the crossing. The frequency of the approaching whistle … 
Science
when you ride in a train that passes a train moving in the opposite direction, the other train appears to rush past you at a greater speed than if you were watching from a parked car at a crossing. how does the speed of your train … 
physics
A train 400 m long is moving on a straight track with a speed of 80.1 km/h. The engineer applies the brakes at a crossing, and later the last car passes the crossing with a speed of 16.9 km/h. Assuming constant acceleration, determine … 
physics
A train 400 m long is moving on a straight track with a speed of 80.1 km/h. The engineer applies the brakes at a crossing, and later the last car passes the crossing with a speed of 16.9 km/h. Assuming constant acceleration, determine … 
Physics
A person standing close to a railroad crossing hears the whistle of an approaching train. He notes that the pitch of the whistle drops as the train passes by and moves away from the crossing. The frequency of the distant approaching … 
Physics
A train is traveling down a straight track at 25 m/s when the engineer applies the brakes, resulting in an acceleration of −1.0 m/s2 as long as the train is in motion. How far does the train move during a 50 s time interval starting … 
Physics
A train blows its horn as it approaches a crossing. A.) if the train engineer observes a frequency of 125Hz and a stationary observer at the crossing observes a frequency of 132Hz, what is the speed of the train?