Question

two 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? (1 point) both balls will swing to the right. the ball on the right will swing to the right. the ball on the left will stop, and the ball on the right will remain still. both balls will swing to the left.

Explanation:

When two objects of the same mass collide elastically (assuming this is an elastic - like collision as in a simple pendulum - ball collision model), the momentum is transferred. The left - moving ball (after being released) has momentum. When it hits the right - hand ball (initially at rest), according to the law of conservation of momentum (\(m_1v_1 + m_2v_2=m_1v_1'+m_2v_2'\), where \(m_1 = m_2=m\), \(v_2 = 0\) and in an ideal elastic - like collision for same - mass objects \(v_1'=0\) and \(v_2'=v_1\)).

Answer:

The ball on the right will swing to the right.