Originally Posted by

**skeeter** since the car is on a flat track, I would say that $\displaystyle x = 240 \, N$ is the horizontal centripetal force that the car exerts on the passenger and $\displaystyle y = 600 \, N$ is the vertical normal force the car exerts on the passenger ... therefore, the passenger's weight, $\displaystyle mg = 600 \, N$ , making the passenger's mass about $\displaystyle 60 \, kg$ (a reasonable figure).

note that $\displaystyle 68.4 \, km/hr = 19 \, m/s$

using the equation ...

$\displaystyle \frac{mv^2}{R} = x

$

68.4 km/h

... $\displaystyle v$ will work out to the desired solution.