Finding velocity when onlu a mass and acceleration is given

[mkmaitla]

Homework Statement

The instruments attached to a weather balloon have a mass of 5.0kg.The balloon is released and exerts an upward force of 98 N on the instruments. I have found that the acceleration is 1.96 m/s/s by F=ma.
After the balloons have accelerated for 10 seconds, the instruments are released. What is the velocity of the instruments at the moment of their release?

Homework Equations

V(sub f)^2=V(sub i)^2 + 2ad
I have tried this but I don't know either velocity or the distance.
or would it be:
V(sub f) = V(sub i) +at

The Attempt at a Solution

V(sub f)^2= 0^2 + (2)(1.96m/s^2)(d)
or
V(sub f)= 0 + (1.96m/s^2)(10s)

 

[Pengwuino]

Be careful, that's not the acceleration. How did you figure out what the acceleration was?

Once you know the acceleration, you also know that

v = v_0 + at

It's assumed to be released from rest, so v_0 = 0. It's a simple matter of letting t = 10 sec. Remember, the question is quite simple since it only asks for what happens at the release.

 

[mkmaitla]

Oh okay. I looked at the calculator wrong for the decimal. So the initial velocity is 0?

 

[Millacol88]

The force exerted by the balloon on the instruments is 98N, but what is the net force after accounting for gravity?

 

[mkmaitla]

is it 10?

 

[Millacol88]

How did you arrive at that? E.G. which equation did you use?