a 150 m long train is moving north at a speed of 20 m/s. a bird flying south at a speed of 5 m/s crosses the train. what is the time taken by the bird to cross the train?
Answers
A train of 150 m length is going north at a speed of 10 m/s, while a parrot is moving south at a speed of 5 m/s parallel to the railway track. What is the time taken by the parrot to cross the train? Still have a question? Ask your own! What is your question? Ad by Gateway Blend What are ludicrous facts that are surprisingly true? Every state holds money that people are owed and haven't claimed and there's an easy way to claim it! Read More 8 ANSWERS Muhammad Hamza Abbasi Muhammad Hamza Abbasi, B.S Applied Physics, NED University of Engineering and Technology (2017) Answered Jan 7, 2018 For these type of 2 body problems it is better to , change the frame of reference. In this case change the reference frame from being stationary to moving with the velocity of the train Let this frame of reference be moving with a speed of 10 m/s . Now lets calculate new velocities of train and parrot. The velocity of train will be zero since the frame of reference and train, both are moving with same velocity. The velocity of parrot will be v=10+5=15 m/s. (As the frame of reference and parrot are moving in opposite direction , we will add both the velocities) . Now the problem has been converted to one body problem A parrot with velocity 15 m/s has to cover a distance of 150 m. Calculate the time required. Using [math]s=vt[/math] [math]t=s/v[/math] [math]t=150/15[/math] [math]t=10 sec[/math] So 10 seconds is the time required by the parrot to cover a distance of 150 m of a moving train with a velocity of 10 m/s