TGV Train Circular Motion Calculations

[shell4987]

Homework Statement

The fast French train known as the TGV (Train Grande Vitesse) has a scheduled average speed of 216 km/h. (a) If the train goes around a curve at that speed and the magnitude of the acceleration experienced by the passengers is to be limited to 0.050g, what is the smallest radius of curvature for the track that can be tolerated? (in km) (b) At what speed must the train go around a curve with a 1.03 km radius to be at the acceleration limit? (in km/h)

Homework Equations

a=v squared/r

The Attempt at a Solution

I tried this problem and for part (a) i got 72 km which didn't turn out to be right, i used the acceleration formula and converted the units to m/s then reconverted them back to km/hr for acceleration, i had it equal to 0.050 m/s squared and for velocirty i had 60 m/s...

for part (b) i used 0.050 m/s squared as the acceleration again and then 1030m as the radius and solved, then converted it back to km/hr and got the answer to be 25.92km/hr

I don't know what I'm doing wrong, can anyone help me out? thanks.

 

[Doc Al]

0.05g means 0.05*(9.8 m/s^2).