either the objects merge or they fly away..

a gameobject is in vertical position and another gameobject in the horizontal position.. the gameobject from the vertical position touches the one in the H' position.. the problem is when they touch they pass through one another and when i have the rigidbody enabled, mere touch and the one in the horizontal position flies away. i want to know a way in which when the Vertical gameobject touches the Horizontal one it just bounce back or does nothing. excuse my poor english, i am just a beginner.. thanks for the help in advance.