Velocity = (distance covered in a direction) / (time to cover the distance)
Since the y-axis is position (distance), the speed at 3 seconds is the slope of the graph at 3 seconds, and NOT its y-value.
The slope is fairly easy to pick off, because the graph is so straight from 2 sec to 5 sec. During that time, the distance shrinks by 10 meters (from 10m to zero). So the slope of that whole piece of the graph is (-10m) / (3 sec).
That's a slope of (10/3 m/s) or 3.33 m/s .
In answer to the question, we can only give the speed at 3 sec, not the velocity, since we have no information about the direction of the motion. Consequently, I would call the speed a positive number. But it's not worth arguing about, so you should just select <em>choice-A </em>and not make a big scene.
Airplane with nose up: The plane's speed through the air is the square root of (80 m/s squared) plus (120 m/s squared. The whole picture is a right triangle, and the plane's speed is the hypotenuse. The angle is the angle whose tangent is (80/120). You can get it from a calculator, a book, a slide rule, or online from the site that rhymes with floogle.
The man pulling the load is also a right triangle. The horizontal component is (hypotenuse) times (cosine of the angle). The vertical component is (hypotenuse) times (sine of the same angle). Fill in what you know, look up the sin and cos of 25 degrees and write those in too, and then you can solve for what you have to find.
You have to know what the temperature of your suroundings first and then you can melt it with the tools you need. yeah that's another thing know what tools you need and then be safe!:D
The answer is cesium oxide
