# Homework Help: Magnitude of Acceleration

1. Oct 6, 2008

### shimizua

1. The problem statement, all variables and given/known data
What is the magnitude of the acceleration of a falling sky diver (mass 62.5kg including parachute) when the upward force of air resistance is equal to one fourth of her weight?

so i know that Fnet=ma but since i do not know what either the Fnet or the a is i have no idea on how to figure it out.

2. Oct 6, 2008

### Kurdt

Staff Emeritus
The force from gravity is the skydiver's weight. The air resistance opposes her weight, therefore the resultant force is the weight minus the resistance. I'm sure you can get acceleration from there.

3. Oct 6, 2008

### shimizua

ok so i tried doing her weight, 62.5 - (62.5/4) and that was wrong and then someone had told me to use gravity with this also so i tried 62.5(9.8)-((62.5*9.8)/4) and that was wrong as well. where am i going wrong?

4. Oct 6, 2008

### Kurdt

Staff Emeritus
Weight and mass are distinct. Weight is mass multiplied by the acceleration due to gravity. The second part of your work has calculated the net force. The question asks for acceleration.