“Weathering is the breaking down of rocks, soil and minerals as well as wood and artificial materials through contact with the Earth’s atmosphere, biota and waters. Weathering occurs in situ, roughly translated to: “with no movement”, and thus should not be confused with erosion, which involves the movement of rocks and minerals by agents such as water, ice, snow, wind, waves and gravity and then being transported and deposited in other locations.”
Weathering processes are of three main types: mechanical, organic and chemical weathering.
The answer to this question is dropping it on a hard surface.
Answer:
Your hands get warm by fire because chemical energy gets converted into heat energy. When the chemical bonds in the wood are released in the air which then mixes with oxygen and emit heat. This is the reason why it is always hot when you go near something that is burning or is up in flames.
Explanation:
Answer: Symbol A
Explanation:
The four symbols described here represent:
- Symbol A shows two dots and a line draw from one not connected to the other. --> this is an open switch. A switch is component of a circuit that is used to open/close the circuit in order to interrupt/allow the flow of current through the circuit. In this case, the switch is open, since the line does not connect the second dot.
- Symbol B shows two dots and a line draw from one connected to the other. --> this is the symbol used to represent the switch when it is closed, so it is a closed switch.
- Symbol C shows vertical lines in the pattern long, short, long, and short with a plus and minus symbol on it. --> this symbol represents a battery, which consists of two or more cells and provides the electromotive force that pushes the electrons along the circuit.
Therefore, the correct symbol representing the open switch is
Symbol A
Answer:
Approximately 21 km.
Explanation:
Refer to the not-to-scale diagram attached. The circle is the cross-section of the sphere that goes through the center C. Draw a line that connects the top of the building (point B) and the camera on the robot (point D.) Consider: at how many points might the line intersects the outer rim of this circle? There are three possible cases:
- No intersection: There's nothing that blocks the camera's view of the top of the building.
- Two intersections: The planet blocks the camera's view of the top of the building.
- One intersection: The point at which the top of the building appears or disappears.
There's only one such line that goes through the top of the building and intersects the outer rim of the circle only once. That line is a tangent to this circle. In other words, it is perpendicular to the radius of the circle at the point A where it touches the circle.
The camera needs to be on this tangent line when the building starts to disappear. To find the length of the arc that the robot has travelled, start by finding the angle 
which corresponds to this minor arc.
This angle comes can be split into two parts:
.
Also,
.
The radius of this circle is:
.
The lengths of segment DC, AC, BC can all be found:
In the two right triangles 
and 
, the value of 
and 
can be found using the inverse cosine function:
.
The length of the minor arc will be:
.
;
;
.
