What is the objects velocity if the momentum is 6.0 kg•m/as

The velocity will be the momentum divided by the mass of the object.

The momentum of an object is defined as the product of its mass and its velocity. And it denoted by p. Its unit is kgm/s

Suppose there is an object that has mass m and is moving with a velocity v, then,  its momentum is given by:

p = mv

according to the question, p = 6 kgm/s but the mass is not given so we will assume the mass to be M.

then its velocity:

v = p/m

v = 6/M m/s

Learn more about momentum:

link

the box does not move because you need to use a force greater than 300 n. you are only using 50 n. it needs to at least be 301 n for the box to move because then it is an unbalanced force and it will move the way that the greater force is pushing it. if you use only 300 n it will be a balanced force and will not move because the force you are exerting on the   box is the same as its force.

hope this !

im sorry if i went too in depth, i am going to include a link to a video on khan academy that will explain this.   hope that you like the video and that it explains more in detail to you.

that is the link.