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## Homework Statement

A 5.3kg mass hangs vertically from a spring with spring constant 720N/m. The mass is lifted upward and released. Calculate the force and acceleration the mass when the spring is compressed by 0.36m.

Note: I already solved for acceleration and I got the correct answer- a=58.70566038m/s^2

I tried to solve for the spring force but I got the wrong answer and I'm not sure what I did wrong.

m=5.3kg, k=720N/m, Δx=0.36m.

## Homework Equations

I used Fnet=ma

## The Attempt at a Solution

Fnet=ma

ma=-Fg-Fx

(5.3)(58.70566038)=-mg-Fx

311.14=-(5.3)(9.8)-Fx

311.14=-51.94-Fx

311.14+51.94=-Fx

363.08=-Fx

-363.08N=Fx

363.08N[down]=Fx

The correct answer is 310N[down]. Can someone tell me what I did wrong? Also, I'm confused about whether a put the negative signs infront of the correct variables(Fg and Fx are both pointing downwards in this problem, so I put a negative sign infront of both). Should I put a negative sign infront of Fnet too since Fnet points downwards in this case? Are you even supposed to put negative signs infront of variables based on direction when doing calculations?