A440 kg roller coaster car is going 26 m/s when it reaches the lowest point on the track. if the car started from rest at the top of a hill, how much higher was that point on the track than the lowest point?

The only thing acting as the roller coaster gets to the bottom is gravity thus
acceleration is 9.81

so u use the formula
vf^2 = vi^2 + 2abetaD
thus
distance = vf^2 - vi^2 divided by 2a
so 26^2 - 0^2 divided by 2(9.81m/s)
equals 676 divided by 2(9.81m/s)
= 34.45463812m
then use the appropriate 3 sig digs
so 34.5m
hopes this helps 

The speed was not exceeded so it was slow

    5.5 n======    assuming that      we have      m = 0.145 kg    a = 38 m/s²therefore    5.51 n, but two significant figures.final answer: 5.5 n