Calculate the retarding force due to the viscosity of the air layer between a cart and a level air track given the following information: air temperature is 20∘C, the cart is moving at 0.400 m/s, its surface area is 2.50×10−2 m2, and the thickness of the air layer is 6.00×10−5 m. Viscosity of air at 20∘C is 1.516×10−5 Pas 3.07×10^−3 N 9.605×10^−3 N 2.503×10^−3 N 6.500×10^−3 N