Question

Two identical trains A and B move with equal speeds on parallel tracks along the equator. A moves from east to west and B moves from west to east. Which train will exert greater force on the track?

• A. A
• B. B
• C. they will exert equal force
• D. the mass and the speed of each train must be known to reach a conclusion

Answer 1

The correct option is A A

When observed from the center of the earth, the trains are observed to follow circular track with radius R and velocity v.angular velocity of earth be $\omega$

Net speed of car A = v-$\omega$R

net speed of car B = v+$\omega$R

Centrifugal force = $\frac{m{v}^2}{R}$

higher the velocity, higher is the centrifugal force, and thus lower the normal force exerted by the train on the track.

Thus, A has a lower net speed, lower centrifugal force and thus higher normal force exerted on the track.