叩く

1. godan verb, transitive to strike; to hit; to beat; to knock; to pound; to bang; to slap; to spank; to tap; to pat; to clap (one's hands); to play (the drums)
2. to attack; to bash; to criticize; to censure; to flame (on the Internet)
3. to sound out (someone's views)
4. to pound (meat or fish); to chop into small pieces
5. to beat down the price
6. as ...口を叩く to talk (big, bad, idly, etc.)
7. computing to call; to invoke (e.g. a function)

はたく

1. godan verb, transitive, usually in kana to dust; to remove dust
2. usually in kana to slap; to hit (with the palm)
3. usually in kana to use up money