# Finding total force - Is this correct?

1. Sep 29, 2011

### nukeman

1. The problem statement, all variables and given/known data

A weight lifter who has a mass of 90kg lifts a weight of 50kg, which accelerates the weight at a rate of 0.47 m/s^2

Would the total force simply be (140kg)*(0.47m/s^2) = 65.8 n?

2. Relevant equations

3. The attempt at a solution

2. Sep 29, 2011

### BobG

That would actually be your net force. You forgot the force of gravity.

Additionally, I don't think the weightlifter is accelerating into the air - only the weight.

3. Sep 29, 2011

### nukeman

ahh, net force.

Can you possibly point me in the right direction for total force for my example?

4. Sep 29, 2011

### nukeman

Can anyone else help me out with this one?

Thanks :)

5. Sep 29, 2011

### BobG

You have the force of gravity on the weightlifter.

You not only have the force of gravity on the weight, but the weightlifter is applying a force to accelerate it.

This would be the total force applied to the floor the weightlifter is standing on.

6. Sep 29, 2011

### nukeman

Thank you... How would I calculate this?

So, I am asking to identify which laws are being used.

This would be Newtons 3rd correct?