Projectile F=ma: -475 N & 3.00x10^3m/s^2 calc force

[balllla]

Homework Statement

what force is required to give a projectile weighing -475 N an acceleration of 3.00x10^3m/s^2

Homework Equations

f=ma

The Attempt at a Solution

f=ma
-175 N=m (-9.81m/s^2)
m=48.4 Kg

f=ma
f=(48.4kg)(3.00x10^3m/s^2)
f=145000 N


hi thanks so much for your help, I'm just wondering if I have completed this correct. I'm am just confused because it says that the projectile weighs -475 N so I have to change that into it's mass then into it's force.

thank you. have a good night.

 

[Cryxic]

Seems like it's right.

 

[GRB 080319B]

This is correct if the applied force F is horizontal. If the applied force F is vertical (upward, against weight), then

\sumF = F - mg = ma
F = m(a + g)