Predict whether the hottest part of a room will be near the ceiling, in the center, or near the floor, given that there is a hot-air vent near the floor.

near the ceiling

Explanation:

Air when heated expands, this means that that the density of air decreases. When the density decreases it rises up. Things of lesser density rise up. This could be understood by considering the case of water. Wood floats because it has less density when compared with water.

In this case all the hot air being pumped in the room will get accumulated at the top of the room, the hot air will not stay at the bottom. This means that the hottest part will be near the ceiling.

answer:   you might love summer weather, but you don’t want it to feel like the sun is inside your car. but a hot car that just won’t seem to cool down might be a bigger of a problem than you think. your car relies on being at the right temperature.

explanation:

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.