# Car going around banked curve with no friction

## Homework Statement

a racecourse is designed with curves with a radius of 200m and a 10degree banking. What is the maximum speed a car can negotiate the curve without friction?

newtons 3 laws

## The Attempt at a Solution

tanTheta = v^2/gR
tan10 = v^2/(9.8 * 200m)
v = 345 m/s^2

is this right?

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tiny-tim
Homework Helper
hi chaotiiic! tanTheta = v^2/gR
tan10 = v^2/(9.8 * 200m)
formula looks ok

are you sure about the 345 ?

(and speed is m/s, not m/s2)

hi chaotiiic! formula looks ok

are you sure about the 345 ?

(and speed is m/s, not m/s2)
so is it 0.1763 = v^2/1960
v^2=345.6
v=18.59m/s

tiny-tim
Homework Helper
yes! (are you ok now, or is there anything you're still not sure about?)​

yes! (are you ok now, or is there anything you're still not sure about?)​
thankyou. :surprised
im actually still confused about everything. the only reason i was able to answer this problem is because there's a problem identical in my book to the one i asked. my teacher gives out quizzes before lectures so hopefully ill understand when i go to class later today.

tiny-tim
Homework Helper
ok, so you don't understand the reason for the formula? …
tanTheta = v^2/gR
like almost all dynamics questions, it all boils down to good ol' Newton's second law (F = ma) …

you know the acceleration (as a function of v),

and although you know the weight, you don't know the normal force …

so you do F = ma perpendicular to the unknown (normal) force 