If saving dropped sharply in the economy, what would likely happen to investment? Why?

Answer:

Savings are actually supposed to finance investment and boost productivity in the economy. If people save more, then banks have more to lend to firms to increase investment.

According to Harrod Domer model, increases savings mean higher investments, which means growth in capital stock, which further mean higher economic growth and which again mean higher savings. Thus a cycle is completed.

So a sharp drop in savings would also bring down the investment activity.

PFA