Please take another look at the coin. The only dual-dated Kennedy halves were struck during the Bicentennial and were dated 1776-1976 - and in any case, JFK was only 9 years old in 1926 so he definitely wouldn't have been on a coin from the Sesquicentennial.
Next, see whether it has a small "D", "S", or no letter between the bottom of JFK's portrait and the date. If it has a D or no letter, it's a standard circulation half made of copper-nickel, not silver, and is only worth 50¢. If it has an S, it could be either copper-nickel or 40% silver. If it has a copper-colored edge it's copper-nickel; plain or grayish would indicate 40% silver. In that case it might be worth about 1/7 the price of 1 oz of silver at the current going rate (which changes a lot).
A 1969 silver Kennedy half dollar is worth $5 inn perfect condition. The value of the silver is worth $2.87.
The 1969 Kennedy half dollar is only 40% silver with a value about $3.25
About $6 for its silver content
The coin is 40% silver and has a value of about $2.00 only for the silver.
If the coin is a US Kennedy half dollar dated 1974 it has no silver in it and is face value.
A 1969 silver Kennedy half dollar is worth $5 inn perfect condition. The value of the silver is worth $2.87.
A 2002-S silver proof Kennedy has an average retail value of $18.00.
If you check the back you'll find that you have a halfdollar. There has never been a US-issued Kennedy silver dollar.
The 1969 Kennedy half dollar is only 40% silver with a value about $3.25
About $6 for its silver content
The coin is 40% silver and has a value of about $2.00 only for the silver.
If the coin is a 1996-S Silver Proof Kennedy Half dollar, average retail value is $12.00 to $15.00
The coin has no silver and is just face value, spend it.
If the coin is a US Kennedy half dollar dated 1974 it has no silver in it and is face value.
Please, turn the coin over and look at the denomination on the back. It's a HALF dollar, not a dollar. The 1964 Kennedy half is a 90% silver coin, but very common. The value would be only for the silver, about $15.00 as of 9-1-11.
About $15.00, retail.
It has no silver and is just 50 cents, spend it.