Question

How large must the coefficient of static friction be between the tires and the road if a car is to round a level curve of radius 89 at a speed of 93 ?

Answer 1

Please post all physics questions with the appropriate units. 89 could be feet (unlikely), metres, and 93 could be miles per hour, km/hr, ft/sec or m/s.

In any case, the centrifugal force for an object moving at a tangential speed of v at a radius or r is
F=mv²/r
The normal reaction between the tires and the road is N = mg.

At the point of tires slipping, the coefficient of static friction is therefore:
μ = F/N

Answer 2

i'm not understanding the equation F=mv^2/r; what would be the m? gravity?

Answer 3

In SI units,
m is mass of object(kg)
v is velocity (m/s)
r is radius of circular motion (m)
F is a force in N
g is acceleration due to gravity (m s^-2
μ is coefficient of static friction.

Can you now give an attempt to solve the problem?

Answer 4

i understood what everything else stood for, i just didn't understand how to use the given equation, F=mv^2/r, when the problem did not specify a value for m. I tried to think of another way to solve for m using the givens, but i was unsuccessful.

Answer 5

m in this case would be the mass of the car.