1. The problem statement, all variables and given/known data Well i have the force which equals 500N and I don't have a given acceleration so should I be substituting 9.81 as the acceleration? or is their another way to find it given that I also have the friction which equals 125N. So which way is the right way of going? 2. Relevant equations F=Ma 3. The attempt at a solution Well what I've done is 500=m x 9.81, which goes to 500/9.81=m, which then gives me 51.02kg, so is that correct because it doesn't seem right to me. Any help would be much appreciated, Thanks.