[填空题]
A roller coaster car with a mass of 80 k+rs(brev,:hentne.ml-:h/ yym:r q 0g moves olytw9 y w*dcct54 ;npy. *cdy*li.x 7yn the track shown in the diagram starting from poi.ty.*y*p d ;xyc l4iyl c*wt9nd 5ycw7nt A.
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. $v_{max}$ = $ms^{-1}$
