on a force-time graph:

Question

rectangle is shaded in from 2 to 8 on the x axis. It is shaded from 0 to 8 on the y axis. (so the base is 2 to 8 and the height is 0 to 8)

The graph is for a force acting on a 12.0 kg cart initially at rest on a frictionless surface.

What is the final velocity of the cart?

Thank you for your help.