Hi. I'm having trouble with this circular motion question. I'll post the full question and then my queries beneath it.

In a “pinewood derby,” children build wooden cars to race on a curved track as shown above. The cars all start at an initial height of 1m. Pulled by gravity (g=9.8 m/s2 ), they travel down a curved track onto a long flat straightaway. The first car across the finish line (at the end of the straightaway) wins. There is a strict limit on the weight of each car: 150 g.

Let us suppose that the initial ramp is shaped like one fourth of a circle with radius=1m. A car is observed at a height of 0.5 m with a speed of 3 m/s.

1. What is the acceleration of the car at this moment?

2. What is the normal acceleration (the normal force / the mass of the car) on the car at this moment?

3. If the coefficient of friction for the car on the track is µ=0.02, what is the acceleration due to friction at this moment?

1.I simply did $\displaystyle a=\frac{v^2}{r} = 9 ms^{-1}$, as at this moment we can treat it as uniform circular motion(?); however, does gravity need to be considered here?

2.I said $\displaystyle N=mg{\cdot}cos(45)+\frac{mv^2}{r}$ and went from there, but I'm unsure if this is the right approach.

3.I know that $\displaystyle F_{r}={\mu}N$, and that it must be in the opposite direction to the net force which is not(?) towards the centre of the circle at this point, but instead in the direction of motion. As such I did $\displaystyle ma={\mu}N$ and solved fora, but I'm really unsure about this.

Any help would be much appreciated.