1. can an object be in motion and have no net force acting on it? explain?

Yes

Explanation:

We can answer this question by using Newton's second law:

where

F is the net force on an object

m is the mass of the object

a is its acceleration

Here we are considering an object which has no net force on it, so

F = 0

Therefore,

a = 0

which means that its acceleration is zero.

However, acceleration is defined as the rate of change of the velocity over time:

where v is the final velocity, u the initial velocity, t the time. If a = 0,

which means that the velocity of the object is constant. However, constant does not necessarly mean zero: therefore, if the object has no net force acting on it, we can only say that its velocity is constant, but it can be either at rest or moving.

its c its is a mixture of gases

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.