Refer to Conceptual Question 17 in Chapter 2. A heavy lead ball hangs from a string attached to a sturdy wooden frame. A second string is attached to a hook on the bottom of the lead ball. In Chapter 2, you imagined pulling slowly and steadily on the lower string and found that the upper string would break first. Now imagine that you reset the apparatus and this time give the lower string a quick, hard pull. Now which string do you think will break first? Explain.