Final answer:
The investor incurs a loss of $1000.
Step-by-step explanation:
When an investor sells a stock short, they borrow the stock from a broker and sell it in the hopes that the price will decrease. If the price does go down, the investor buys the stock back at a lower price and returns it to the broker, making a profit. However, if the price goes up, the investor incurs a loss. In this case, the investor sold 100 shares of stock short at $50 and the price rose to $60. Therefore, the investor incurred a loss of $10 per share, resulting in a total loss of $1000.