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, from west to east. Which train will exert greater force on the tracks?

• 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

Let $v=$ speed of each train relative to the earth's surface,
$v_E=$ speed of earth's surface relative to the earth's axis,
$v_A,v_B=$ speed of A and B relative to the earth's axis.
The, $v_A=v_E-v_B=v_B+v.$
$N_A=mg-m\left(\frac{v_A^2}{R}\right),N_B=mg-m\left(\frac{v_B^2}{R}\right)$
$\therefore N_A>N_B$.