The Physics of Tobogganing Part 4

On the same day that we went tobogganing at Hamstead Park, a small French family joined in the cold fun : ). The picture below shows a little girl and her father on their way down the snowy hill.

Very simple explanation of the physics involved in this situation. The same previously explained concepts apply including Newton's Laws and Work. However, in this case, weight and normal force are greater than those of one person on the toboggan. The vertical component of the force of gravity mg cancels the normal force N. Thus, the force that causes the motion downwards is mgsin(theta). Although weight mg is constant, kinetic friction, and wind resistance slows my cousin down. Because the contact between the toboggan and the snow / ice creates a frictional force that is directed opposite (back up the hill), the force decreases their rate of acceleration. Work is still the equation W=fx where the w= [mgsin(theta) - f(friction)]x. Hence, the only difference is that the value of mg is greater because instead of one person, there are two.