What formula should i use to calculate the loss in kineti energy during braking and the power dissipated as heating in the brake do i just use ke=1/2mv^2 and work done =force x distance ?
Yes. The braking force x stopping distance (assuming constant braking force) is equal to the loss of kinetic energy of the vehicle. AM
And if it's not constant, you can integrate the dot product of the force vector and the differential x-vector. If you want the power of heat generation, you will need to find how much energy is being dissipated (i.e. how much kinetic energy is lost) per unit of time.