1. The problem statement, all variables and given/known data Calculate the acceleration of a plane weighing 9800N when the forward force is 210000N, the drag force due to air resistance is 500N 2. Relevant equations F=ma 3. The attempt at a solution the mass is 1000kg as 9800/9.8 is 100. The resultant force R must be 210000-500=209500 So is the acceleration 209500/1000 or 209500/9800? 209599/9800=21.38ms^2 so that makes a lot more logical sense than 209.5ms^2 But force=massXaccelration not force=weightXacceleration. I know its another basic question but please someone help stop my head hurting.