Question

The force needed to keep a car from skidding on a curve varies inversely with the radius of the curve and jointly with the weight of the car and the square of the speed. If 412 LB of force keeps a 1500 pound car from skidding as it travels at 35 miles per hour on a curve of radius 300 feet, what force would keep the car from skidding on a curve of radius 650 feet at 60 miles per hour?

Answer 1

first you need to establish the actual equation from the words

force varies inversely with radius
force varies directly with mass
force varies with speed squared

SO - can you write the equation for
Force = (some function of M, V^2 & r) ??

Incidentally the terminology of this question is appalling. It is the MASS that it varies with NOT the weight, and also Pound is not a unit of force - it is a unit of mass - so do they mean the force in Poundals or in lbf

It is very poor for question setters to be so imprecise in a subject which relies on precision. I really don't know whether to use poundals or lbf to calculate the answer.

BTW Also - whilst I know the US is stuck in the past with lbs and feet etc. but if you get used to the metric system you will find that the units and conversions are very much more straight forward.