PhysicsUtils.cs

using System;
using UnityEngine;

public static class PhysicsUtils
{
    public static Vector3 Accelerate (this Rigidbody rigidbody, Vector3 targetVelocity, float acceleration,
        float minSpeed = .05f, bool preserveY = false, bool preserveX = false, bool canDecelerate = true)
    {
        if (rigidbody == null || rigidbody.isKinematic)
            return Vector3.zero;

        var velocity = rigidbody.velocity;
        var oldY = velocity.y;
        var oldX = velocity.x;

        var deltaVelocity = targetVelocity - velocity;
        var deltaVelocityMag = deltaVelocity.magnitude;
        var deltaVelocityDir = deltaVelocity / deltaVelocityMag;
        var frameVelocityMagChange = acceleration * Time.deltaTime;

        if (frameVelocityMagChange < deltaVelocityMag)
            velocity += deltaVelocityDir * frameVelocityMagChange;
        else velocity = targetVelocity;

        float sqrSpeed = velocity.sqrMagnitude;

        if (acceleration == 0f && sqrSpeed < minSpeed * minSpeed)
            velocity = Vector3.zero;

        if (preserveY)
            velocity.y = oldY;
            
        if (preserveX)
            velocity.x = oldX;

        rigidbody.velocity = velocity;
        return velocity;
    }

    public static Vector3 GetTriggerHitLocation (Collider self, Collider target, TriggerHitLocationMode hitLocationMode)
    {
        Vector3 location = Vector3.zero;

        if (hitLocationMode == TriggerHitLocationMode.AtSelf)
            location = self.transform.position;
        else if (hitLocationMode == TriggerHitLocationMode.AtTarget)
            location = target.transform.position;
        else if (hitLocationMode == TriggerHitLocationMode.Midpoint)
            location = (self.transform.position + target.transform.position) / 2;

        return location;
    }
}