Rigidbody force problem

Hello everyone,i have a rigidbody on the car model , and i want to be affected by the car and i want to be forced to another direction by the car when i hit it but :

 rigidbody.AddForce (Vector3.up * 10);

just doesn't work, any other thing i can do for this ?

i thought i can do it with translate but how ?

Add more force. I mean, a lot more. Also look at the ForceMode options.