[填空题]
A roller coaster car with a mass oi k:sdy7n yy/k-r9f) c)w7 r pv0+helaf 80 kg moves o +)na z/ixeqojstr084n the track shown in the diagram starting from point q+/ezoai t8 sr)n j0x4A.
At points B and C, the track approximates a circular path so that the radii at at B and C are $12,m$ and $18\,m$ respectively.
1.Compare the normal force exerted by the track on the car at point B is the corresponding force at point C.
2.Draw and label the free body diagram of the car at point C.
3.Calculate the maximum speed of the car at point C so that it could remain on the track. $v_{max}$ = $ms^{-1}$
