Two rails of a railway track insulated from each other and the ground are connected to a milli voltmeter. What is the reading of millivoltmeter when the train travels at speed of 180 km/h along the track, given that the horizontal component of earth's magnetic field is `0.2*10^(-4)` wb/m and the rails are separated by 1 meter.

A wheel with 25 metallic spokes each 0.4m long is rotated with a speed of 150 rev//min in a plane normal to the horizontal components of earth's magnetic field H_B at a place. If H_E=0.4G at the place, what is the induced emf between the axle and the rim of the wheel?

A trolley of mass 200 kg moves with a uniform speed of 36 km/ h on a frictionless track. A child of mass 20 kg runs on the trolley from one end to the other (10 m away) with a speed of 4 m s^-1 relative to the trolley in a direction opposite to the its motion, and jumps out of the trolley. What is the final speed of the trolley? How much has the trolley moved from the time the child begins to run?

Two inclined frictioniess tracks, one gradual and the other steep meet at A from where two stones are allowed to slide down from rest, one on each track (Fig. 6.16). Will the stones reach the bottom at the sam time? Will they reach there with the same speed? Explain. Given 0?t = 30°, 0_2 = 60°, and h = 10 m, what are the speeds and times taken by the two stones?

Two trains A and B of length 400 m each are moving on two parallel tracks with a uniform speed of 72 km h^-1 in the same direction, with A ahead of B. The driver of B decides to overtake A and accelerates by 1 m//s^-2 . If after 50 s, the guard of B just brushes past the driver of A, what was the original distance between them?