# Homework Help: Calculating acceleration of a plane weighing 9800N

1. Oct 15, 2012

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.

2. Oct 15, 2012

### lendav_rott

1 tonne for a plane is kind of light so that's probably why you're getting such a quick acceleration. I mean even if you didn t take the air resistance into account, the output of energy by the engine is waaaay to big for 1000kg -s of mass.

I think the engine alone would have to weigh alot more than that