- #1

Monocles

- 466

- 2

**[SOLVED] very simple drag question**

## Homework Statement

A ping pong ball of mass m is thrown downward at twice it's terminal speed. What is its magnitude of acceleration immediately after release in terms of m and any other physical or mathematical constants?

## Homework Equations

This was a quiz question, the only ones I could think of were

D = 1/4Av^2

Sum of Forces = ma = D - mg

## The Attempt at a Solution

Since we weren't given a drag coefficient or area of the ping pong ball I had no idea how to proceed. All I knew is that we were allowed to use the ball's mass and any other physical or mathematical constants to solve it. Since mass was the only given quantity allowed I figured that it wasn't involved in the solution because mass isn't a dimension of acceleration. I couldn't find the drag force on the ball, so I just wrote that the magnitude of acceleration was g. It was pretty much a pure guess. Maybe this is the correct answer, but this is only question on the quiz I had no idea how to do so I wanted to ask here as soon as possible :)