Acceleration of Transform in FixedUpdate (SOLVED)

im trying to get the acceleration of the transform of a gameobject in FixedUpdate. i need it for a raycast wheel i am trying to create. i already get the velocity of it through a code i found in the web. ive been searching all day now and i still havent figured out how to calculate the acceleration of a transform.

here is what i used to calculate the transform's velocity:

 IEnumerator CalcVelocity()
 {
     while (Application.isPlaying)
     {
         // Position at frame start
         prevPos = transform.position;
         // Wait till it the end of the frame
         yield return new WaitForSeconds(Time.fixedDeltaTime);
         // Calculate velocity: Velocity = DeltaPosition / DeltaTime
         currVel = (prevPos - transform.position) / Time.fixedDeltaTime;
         localVel = transform.InverseTransformDirection(currVel); 
     }
 }

(sorry, can't figure out how to make a code sample)

thanks if you take time to help me

EDIT: this is how i solved it:

 IEnumerator CalcVelocity()
 {
     while (Application.isPlaying)
     {
         Vector3 pos1 = transform.position;
 
 
         yield return new WaitForFixedUpdate();
 
         Vector3 pos2 = transform.position;
 
         Vector3 vel1 = (pos1 - pos2) / Time.fixedDeltaTime;
 
         deltaPos = pos1 - pos2;
 
         currVel = vel1;
 
         localVel = transform.InverseTransformDirection(currVel);
 
 
         yield return new WaitForFixedUpdate();
 
         Vector3 pos3 = transform.position;
 
         Vector3 vel2 = (pos2 - pos3) / Time.fixedDeltaTime;
 
         Vector3 acc = (vel1 - vel2) / Time.fixedDeltaTime;
 
         currAcc = acc;
 
         localAcc = transform.InverseTransformDirection(currAcc);
 
 
     }
 }