# Relation between Torque, Speed, power etc. respect to a electric car

## Main Question or Discussion Point

hey guys,

I am building an electric go kart for a final project, and i'm just trying to get my initial justifications correct, with respect to the classical physics involved.

SPECS: i was the car to be able to reach 15km/h,
The total weight of the car will be approx 200kgs.
the size of the tires of the car are 30 cm in diamator.

Motor Type: BLDC Motor
Maximum Power: 350 Watt
Max. Operating voltage: 48v

so i need to calculate the torque... at the wheels , and then decide on the gearing ratio! this decision is obviously indicative on the parametors of the motor i have! and the goals i want to achieve! The Motor i have has a max RPM of 4000, and a peak torque of 12NM.

can anyone show me best how to perform these calculations ? i understand that i need acceleration ! can i assume constant acceleration ? if that is the case can i just say i would like the car to accelerate to 15km/h in 10 seconds

... any help will be much appreciated !
Thank You

## Answers and Replies

Related Electrical Engineering News on Phys.org
If this is your final project these should be easy to figure out -

1 estimate speed of the go-cart to the rpm of the wheel, then compare to the motor max speed.

2 acceleration will depend on the torque and then force where the wheel meets the road...