Q21 of 35 Page 55

A 150m long train is moving to the north at a speed of 10 ms–1. A parrot flying towards the south with a speed of 5 ms–1 crosses the train. Calculate the time taken by the parrot to cross the train.

Speed of train towards north = 10 ms–1

The speed of parrot towards north = 5 ms–1


Now, the speed of train = = 10 ms–1 and Speed of parrot = = –5 ms–1 (Due to the opposite direction)


Now, spthe eed of parrot with respect to the train


=


(Considering only the magnitude)


So, Distance to be travelled = Length of train = 150 m


And speed =


Now, Time =


So, time taken by the the parrot to cross the train is 10 s.


More from this chapter

All 35 →
19

A particle starting from rest undergoes a rectilinear motion with acceleration a. The variation of ‘a’ with time t is shown below. The maximum velocity attained by the particle during its motion is. (a = 10 ms–2 and t = 12s)

 20

A person goes to his office from his home daily at a fixed speed. But today he decided to reduce his speed by 20%. As a result he reaches his office 16 minutes late. What's the actual time he takes to reach his office daily?

 22

The acceleration of a particle is increasing linearly with time t as (b×t). The particle starts from origin with an initial velocity u. The distance travelled by the particle in time t will be?

 23

A body travels a distance of 2 m in 2 s and 2.2 m in next 4 s. What will be the velocity of the body at the end of 7th second from the start?