At what angle must a railway track with a level of 300 m radius be banked for safe running of trains at a speed of 90 km h^(-1) ?

At what angle must a railway track with a level of 300 m radius be ban

1.	At what angle must a railway track with a level of 300 m radius be banked for safe running of trains at a speed of 90 km h^(-1) ?
Answer» SOLUTION :`r=300 m, v= 90 KM h^(-1) = 25 MS^(-1), theta` = ? `tan theta = v^(2)/(rg) = (25 xx 25)/(300 xx 9.8)= 0.2126, theta = tan^(-1) (0.2126) = 12^(@)`