Teo metal balls with the same mass hang so that they are touching each other. The ball on the left is pulled to the side and released. What will happen when it swings back and hits the ball on the right

When the ball on the left is pulled to the side and released, it will swing back towards the right ball due to the force of gravity and potential energy being converted to kinetic energy. When the swinging ball reaches its highest point on the right side, it will momentarily stop before swinging back down. At this point, it will transfer some of its kinetic energy to the stationary right ball, causing the right ball to start moving. As a result, both balls will continue to swing back and forth, transferring energy between each other until eventually coming to rest due to energy losses from friction and air resistance.