14.7 Exercise 6

(a) 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 $20 °\text{C}$, the cart is moving at 0.400 m/s, its surface area is $2.50 \times 10^{−2} \text{m}^{2} ,$ and the thickness of the air layer is $6.00 \times 10^{−5} \text{m}$. (b) What is the ratio of this force to the weight of the 0.300-kg cart?