Answer:
True the plastic will float because of the principle of flotation or buoyancy
Explanation:
Buoyancy explains it all!!
Buoyancy  is the upward force/upthrust experienced by a body immersed totally or partially in a liquid.
According to the principle of flotation:
<em>"when a body is totally or partially immersed in liquid it experiences an upthrust which is equal to the volume of fluid displaced"</em>
The plastic will float due to the fact the average density of the total volume of the plastic and the air inside it is less than the same volume of water it is floating in
 
        
             
        
        
        
Answer:
The center of mass of the Earth-Moon system is 4.673 kilometers away from center of Earth.
Explanation:
Let suppose that planet and satellite can be treated as particles. The masses of Earth and Moon ( ,
,  ) are
) are  and
 and  , respectively. The distance between centers is 384,403 kilometers. The location of the center of mass can be found by using weighted averages:
, respectively. The distance between centers is 384,403 kilometers. The location of the center of mass can be found by using weighted averages:

If  and
 and  , then:
, then:


The center of mass of the Earth-Moon system is 4.673 kilometers away from center of Earth.
 
        
             
        
        
        
Answer:
IMA = 2.5 metres
EFFICIENCY = 80%
Explanation:
The AMA of a machine is referred to as the Actual Mechanical Advantage of a machine, calculated as the ratio of the output to the input force. 
The Ideal Mechanical Advantage is the ratio of the input distance to the output distance. 
From the diagram, the input distance which is also the distance moved by effort  = 5metres 
The load distance (output distance) = 2 metres 
IMA = INPUT DISTANCE / OUTPUT DISTANCE 
IMA = 5metres / 2 metres = 2.5 meters 
Efficiency is the ratio of AMA TO IMA 
AMA = 2, IMA = 2.5
EFFICIENCY = AMA / IMA
EFFICIENCY = (2 / 2.5) × 100%= 0.8 × 100%
EFFICIENCY = 80%
 
        
             
        
        
        
<h2>
Answer: higher mean annual rainfall and temperatures. </h2>
Explanation:
Chemical weathering is the set of destructive processes through which rocky materials go trhough. These processes cause changes in the color, texture, composition, firmness and shape of the material.
It should be noted that this happens when the rocks come into contact with atmospheric agents such as oxygen and carbon dioxide.
Another important aspect is that rocks are able to break up more easily thanks to this type of weathering, since <u>the mineral grains within the rock lose adherence and dissolve better under the action of some physical agents</u>, such as <u>humidity (rainfall included) and temperature</u>.
Therefore:
Chemical weathering is greatest under conditions of <u>higher mean annual rainfall and temperatures. </u>