A train moving at 72 km/h passes a platform 300 m long. How long does it take to cross the platform completely?
Practice Questions
1 question
Q1
A train moving at 72 km/h passes a platform 300 m long. How long does it take to cross the platform completely?
10 seconds
15 seconds
20 seconds
25 seconds
Total distance = Length of train + Length of platform. If length of train is L, time = (L + 300)/20 m/s. Assuming L = 300 m, time = (300 + 300)/20 = 30 seconds.
Questions & Step-by-step Solutions
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Q
Q: A train moving at 72 km/h passes a platform 300 m long. How long does it take to cross the platform completely?
Solution: Total distance = Length of train + Length of platform. If length of train is L, time = (L + 300)/20 m/s. Assuming L = 300 m, time = (300 + 300)/20 = 30 seconds.
Steps: 4
Step 1: Convert the speed of the train from km/h to m/s. To do this, divide the speed by 3.6. So, 72 km/h ÷ 3.6 = 20 m/s.
Step 2: Identify the total distance the train needs to cover to completely cross the platform. This distance is the length of the train plus the length of the platform. We assume the length of the train is 300 m, so total distance = 300 m (train) + 300 m (platform) = 600 m.
Step 3: Use the formula for time, which is time = distance ÷ speed. Here, distance = 600 m and speed = 20 m/s.
Step 4: Calculate the time taken to cross the platform. So, time = 600 m ÷ 20 m/s = 30 seconds.
