Finding distance/work if only given mass and force?

[medbum]

Homework Statement

You try to lift a block of concrete that has a mass of 80 kg, and you end up producing 700 N of upward force on the block. You do not have any help from levers or pulleys or other machines. How high (if at all) did you manage to lift the block?

Homework Equations

Work=Force * Distance or F=ma

The Attempt at a Solution

I tried assuming that t=1 since I wasn't given time so I tried solving for acceleration and ended up with 4 meters being lifted up. I don't know how to solve for work either since I need the number of meters to solve for it (1 N*m=1 J).

 

[PhysicoRaj]

I think the answer is zero.
For, the Earth attracts it with a force that is equal to = m*g =80*9.8=784 N
Since the max force is 700 N, I think the block can't be lifted.