Calculating Force and Velocity of a Launched Water Balloon

[Mike_r]

I don't know if people on these forums usually do this, but I have a question and nobody is really around to help, ok, here goes,

An elastic puts an upward force of 12N on a 400g balloon. The force lasts 0.15s.

a. draw the free body diagram
b. calculate net force and acceleration
c. what is the velocity of the water balloon when launched from the elastic
d. how high does it go?

I am very stumped on this one, so any help would be greatly appreciated.

 

[Mattowander]

What is the first step?

Draw a free body diagram. List all the forces acting on the object.