how to push a rigidbody

in my game player is pushing a rigid body.am not applying any force .just given heavy mass to the player . all was fine the player can successfully pushes the object.But what my problem is whenever the rigid body attached to the other rigid body do their physics some shake (i mean jerk like vibration) moment is coming. I need to avoid it . how can i do it.

some people said that whenever a physics body is attached to other one that jerk has come no way to prevent it.you need to go in other way.

if it not possible with rigid body try to suggest me other way also.............

thanks for reading