Answer to Take A Stab At It...

     Nefarious Nofingers Ned, the knife-flinging nabob  of Nashville, Nebraska, has turned the tables on his neighbor, Dapper Dan. 

     Ned is an expert...something spurts every time he throws! 

     If Ned throws his 400-g knife with a force of 80 N acting over a time of 0.2 seconds, with what velocity does the knife leave his hand? 

Impulse equals change in momentum.
Impulse = Ft = (80 N)(0.2 s) = 16 Ns
   = 16 kg-m/s

 v = (mv) / m 
    = (16 kg-m/s) / (0.4 kg)
    = 40 m/s

 
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