posted by becky on .
A 2000-kg car rounds a circular turn of a radius 20m. if the radius flat and the coefficient of friction between tires and road is .70, how fast can the car go without skidding?
centripetal force = frictional force
m v^2/r= mg*mu
solve for v.
um i was wondering..do i need to convert like 20m or 2000kg to anything before i do any of it?
In this case, the figures are given in SI units (meters and kilograms), so you could just work with the given figures.
But it is better to solve for v in terms of r, g and mu (the mass drops out). Then you plug in the figures including the units. So, instead of putting r = 20 and g = 9.81, you insert r = 20 m and g = 9.81 m/s^2 in your formula. Then you obtain an answer for v that automatically has units.