When the train passes through a bridge or platform or tunnel or a stationary object having some length If length of train = x meters and length of the stationery object = y meters. Also, speed of the train is z km/hr, then time taken by the train to pass the stationary object having length y meters. = (length of the train + length of stationary object)/speed of the train = (x meters + y meters)/z km/hr Note: Change km/hr to m/sec. Solved examples to calculate when the train passes through a bridge or a stationary object having some length. 1. A train 175 m
long crosses a bridge which is 125 m long in 80 seconds. What is the speed of
the train? Solution: Length of the train = 175 m. Length of the bridge = 225 m Distance covered by the train to cross the bridge = (175 + 225) m = 400 m Time taken by the train to cross the bridge = 80 seconds Speed = distance/time = 400/80 m/sec = 5 m/sec. 2. A train 220 m long is running at a speed of 36 km/hr. What time will it take to cross a 110 m long tunnel? Solution: Length of the train = 220 m Length of the tunnel = 110 m Therefore, length of the train + length of the tunnel = (220 + 110) m = 330m Speed of the train = 36 km/hr Speed of the train = 36 × 5/18 m/sec = 10 m/sec Therefore, time taken by the train to cross the tunnel = 330 m/10 m/sec. = 33 seconds. 3. Find the time taken by 150 m long train passes through a bridge which is 100 m long, running at a speed of 72 km/hr. Solution: Speed of train = 72 km/hr = 72 × 5/18 m/sec = 20 m/sec In order to cross a bridge of length 100 m, the train will have to cover a distance = (150 + 100) m = 250 m Thus, speed = 20 m/sec and distance = 250 m Time = distance/speed = 250m/20 m/sec = 25/2 sec = 12.5 sec. 4. A 90 m long train is running at a speed of 54 km/hr. If it takes 30 seconds to cross a platform, find the length of the platform. Solution: Speed of the train = 54 km/hr = 54 × 5/18 m/sec = 15 m/sec Time taken to cross the bridge = 30 sec Distance covered by train to cross the platform = speed × time = (15 × 30) m = 450 m To cross the platform, train covers a distance = length of train + length of platform 450 m = 90 m + length of platform Therefore, length of platform = (450 – 90) m = 360 m Speed of Train Relationship between Speed, Distance and Time Conversion of Units of Speed Problems on Calculating Speed Problems on Calculating Distance Problems on Calculating Time Two Objects Move in Same Direction Two Objects Move in Opposite Direction Train Passes a Moving Object in the Same Direction Train Passes a Moving Object in the Opposite Direction Train Passes through a Pole Train Passes through a Bridge Two Trains Passes in the Same Direction Two Trains Passes in the Opposite Direction 8th Grade Math Practice From Train Passes through a Bridge to HOME PAGE
Didn't find what you were looking for? Or want to know more information about Math Only Math. Use this Google Search to find what you need.
|