Use the concepts of gross investment and net investment to distinguish between an economy that has a rising stock of capital and one that has a falling stock of capital. "In 1933 net private domestic investment was minus $6 billion. This means that in the particular year the economy produced no capital goods at all." Do you agree? Why or why not? Explain: "Though net investment can be positive, negative, or zero, it is quite impossible for gross investment to be less than zero."