Two trains run at the same speed `v = 90 km//h` along a strainght track one after the other with a separation `l = 2 km`. At the instant when they are located symmetrically relative to the point A at a distance `b = 1 km` form the track, both emit a brief signal of frequency `n = 500 Hz`. What will be the nature of the sound at A? The speed of sound is `V = 350 m//s`

Two electric trains run at the same speed of 72 km h^-1 along the same track and in the same direction with a separation of 2.4 kin between them. The two trains simultaneously sound brief whistles. A person is situated at a perpendicular distance of 500 m from the track and is equidistant from the two trains at the instant of the whistling. If both the whistles were at 500 Hz and the speed of sound in air is 340 m s^-1 , find the frequencies heard by the person.

Two trains are travelling towards each other both at a speed of 90 km h^-1 . If one of the trains sounds a whistle at 500 Hz, what will be the apparent frequency heard in the other train ? Speed of sound in air = 350 m s^-1.

A train is running at a constant speed of 90 km/h on a straight track. A person standing at the top of a boggey moves in the direction of motion of the train such that he covers 1 meters on the train each second. The speed of the person with respect to ground to -

A train is moving with a constant speed along a circular track. The engine of the train emits a sound of frequency f. The frequency heard by the guard at the rear end of the train.

Two trains, each having a speed of 30 km/h, are headed at each other on the same track. A bird that can fly 60 km/h flies off the front of on train when they are 60km apart and heads directly to the other train. On reaching the train, the bird flies back to the first train. What is the total distance the bird travels before the train collide?

A train covers a distance of 200 km with a speed of 10 km/h. What time is taken by the train to cover this distance?

Train X running at 50 km h leaves station A at 11 a.m and train Y running at 90 km/h on parallel tracks leaves station A at 3 p.m. on the same day and in the same direction. After what distance from station A will both the trains be together?