1. The problem statement, all variables and given/known data After scoring a touchdown, an 84.0-kg wide receiver celebrates by leaping 1.20 m off the ground. How much work was done by the wide receiver in the celebration? 2. Relevant equations W= FD 3. The attempt at a solution I know that the correct answer should be: (84.0 kg)(9.80 m/s2)(1.20 m)=988 J I'm just wondering why the acceleration for the wide-receiver is 9.8m/s^2. If his acceleration is 9.8 and the acceleration of gravity is 9.8, wouldn't the total acceleration be 0? Also, when a person jumps, he starts off with a positive velocity which decreases, so shouldn't his acceleration be negative?