## Essential University Physics: Volume 1 (3rd Edition)

We know that the strap is at 15 degrees, so we use trigonometry to find the values of gravity and the centripetal force that make the angle 15 degrees: $tan(15)=\frac{ma_r}{mg}$ $tan(15)=\frac{a_r}{g}$ $a_r=2.63$ We find the velocity: $v=\sqrt{a_rr}=\sqrt{2.63\times 150}=19.85\ m/s=71.484 \ km/h$ This is greater than the speed limit of the train.