Un avión que vuela horizontalmente a 900 km h-1 y a una altura de 1000 m deja caer una bomba. En ese mismo instante, un cañón que se encuentra en la vertical del avión, dispara un proyectil con una velocidad que forma un ángulo de 60° con la horizontal. Admitiendo que las trayectorias de los dos móviles están en el mismo plano vertical

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.

the answer is 12 as i may remember

: )

at right angles to each other