Hi
you need to know what part of the gravitational force covers the centripetal force and what part is exerted on the snow
F=mg-mv^2/r=m(g-v^2/r)
plug the numbers in :
F=75(9.81-(40/3.6)^2/15)=118.47 rounds to 118
don't forget to change the speed from km/h to m/s (divide by 3.6)
The force is going down btw (I suppose you know that but the original question asks for the direction)