# Finding velocity when onlu a mass and acceleration is given

1. Nov 18, 2011

### mkmaitla

1. The problem statement, all variables and given/known data
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?

2. Relevant equations
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

3. 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)
1. The problem statement, all variables and given/known data

2. Relevant equations

3. The attempt at a solution

2. Nov 18, 2011

### 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.

3. Nov 18, 2011

### mkmaitla

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

4. Nov 18, 2011

### Millacol88

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

5. Nov 18, 2011

### mkmaitla

is it 10?

6. Nov 18, 2011

### Millacol88

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