Power up button

hello,i've been trying to create a power up button that adds more speed to the player's speed,but i can't figure out how to acces and modify the speed float from one script to the one that activates when the button is pressed,this is the code that i have untill now

public class AbilitySpeedUsed : MonoBehaviour { // this is used to make a reference to ability speed lock script,and the unlock script

 public AbilityLock locked;
     public AbilityUnlock unlocked;
  //multiplier for how many times the player speed

 public float multiplier =1.4f;
 // Start is called before the first frame update
   
  public void AbilityUsedSpeed()
 {
   //sets the button to not be interactible again
     locked.enabled = true;
         Debug.Log("powerspeed");
         unlocked.enabled =false;
  pickup();
 }
  
  //pickup function is where the player clicks the button and gets the boost in speed
  void pickup()
  {

    Debug.Log("YouUsedthespeedbutton");
 //ads speed to the already constantly moving player
    (gameobject().Playermovement().forwardforce * multiplier);
   
      
    
     
  }

  }
  

and the script to where the float is

      public class PlayerMovement : MonoBehaviour  


 {// This is a reference to the Rigidbody component called "rb"
 public Rigidbody rb;

 public float forwardForce = 2000f;    // Variable that determines the forward force
 public float sidewaysForce = 500f;  // Variable that determines the sideways force

 // We marked this as "Fixed"Update because we
 // are using it to mess with physics.
 void FixedUpdate ()
 {
     // Add a forward force
     rb.AddForce(0, 0, forwardForce * Time.deltaTime);

     if (Input.GetKey("d"))    // If the player is pressing the "d" key
     {
         // Add a force to the right
         rb.AddForce(sidewaysForce * Time.deltaTime, 0, 0, ForceMode.VelocityChange);
     }

     if (Input.GetKey("a"))  // If the player is pressing the "a" key
     {
         // Add a force to the left
         rb.AddForce(-sidewaysForce * Time.deltaTime, 0, 0, ForceMode.VelocityChange);
     }

     if (rb.position.y < -1f)
     {
         FindObjectOfType<GameManager>().EndGame();
     }
 }

}