A Car Is Traveling on a Curve That Forms a Circular

Multiple Choice

A car is traveling on a curve that forms a circular arc. The force F needed to keep the car from skidding is jointly proportional to the weight $\text {W }$
Of the car and the square of its speed s, and is inversely proportional to the radius r of the curve. A car weighing 2,500 lbs travels around a curve at 70 mi/h. The next car to round this curve weighs 4,900 lbs and requires the same force as the first car to keep from skidding. How fast is the second car traveling?

A) $49 \mathrm { mi } / \mathrm { h }$
B) $50 \mathrm { mi } / \mathrm { h }$
C) $44 \mathrm { mi } / \mathrm { h }$
D) $54 \mathrm {~min}$
E) $52 \mathrm { mi } / \mathrm { h }$