Energy formulas. Help me to clear a huge confusion!

Archive SAT Subject Test Preparation
1

<p>When K(i) and U(f) is zero? When K(f) and U(i) is zero?</p>

<p>K(i)+U(i)=K(f)+U(f)</p>

<p>I am utterly confused in this!</p>

2

<p>bump! Anyone?!</p>