This is my science test to see how gravity effects moving items from a ramp

I thought my car would go 46 cm and it went 47 cm my buddy helped me set up the ramp as I sent down the toy car and what else I did was I had to measure how far it went to make sure it went the right distance I measured how long and tall the ramp was 5 cm tall and 10 cm long and with the pressure of gravity push pulling down the car it made the car build up speed as it gone down the ramp making it so when it touched the ground the car kept moving cu the wheels kept spinning and also the car was moving out of fast speed causing it and to go till the car went very slow.