Bigbulls pretty much hit it on the head.

With short shots on low poundage bow you'll probally want to look into a heavier arrow and broadhead for penetration on elk. While a light arrow and light broadhead will get in there. A heavier broadhead will hold that kenetic energy to break 1/2" ribs and penetrate deep into the body cavity and the chance of a exit wound is alot better.

One of the best bone breaker broadheads for recurves and low poundage bows is the ole bear razorhead. With the flat chisel point it busts through ribs and drives straight into the lungs with less deflection. Most high velocity bows today have compensated for weight by speed.

Like bigbulls said keep your shots close and broadside and you got yourself a bull. Goodluck on your hunt.