I do not agree with the statement.
The "substance" can be a compound. It's "pure"
as long as there's nothing else in it but its name.
'Pure' water is 100% H₂O with nothing else in it.
'Pure' table salt is 100% NaCl with nothing else in it.
'Pure' carbon dioxide is 100% CO₂ with nothing else in it.
These example substances are all compounds, not elements.
Answer:
960J
Explanation:
Given parameters:
Force = 120N
Distance = 8m
Unknown:
Work required = ?
Solution:
The work done by a body is the force applied to move a body in a specific direction.
Work done = Force x distance
Insert the parameters and solve;
Work done = 120 x 8 = 960J
Hot air has a lower density than the surrounding atmosphere, therefore,it will rise.. The reason it is "cold" in the upper atmosphere is actually because of a lower air density.
Answer: harder
Explanation: nothing is impossible, therefore is harder because the absence of light will not ¨reflect¨the colors to the retina of the eyes
