A railway car wheel is made by getting a solid steel wheel of diameter d=75cm and covering the rim of the wheel with a thin (0.5 cm) ring of hard steel. To do so, the ring is heated to 400°C. At that temperature it has an inner diameter identical to that of the cold wheel (75 cm). After putting the ring on the wheel, it was cooled back down to room temperature. The coefficient of linear expansion of the steel is α=1.2×10⁻⁵K⁻¹ and the elastic constant of a strip of steel with the same cross section and length as the ring is k =2.1×10⁷N/m. What force one would need to slide the ring off the wheel (in the direction parallel to the axis)? The coefficient of friction of steel on steel is μ=0.8.