Answer:
1. A substance that can be separated into two or more substances only by a chemical change is a(n) _____.
solution
element
mixture
compound
2.
Which of the following materials is a substance?
air
gasoline
stainless steel
silver
3.
The first figure in a properly written chemical symbol always is _____.
boldfaced
capitalized
italicized
underlined
4.
Which of the following represents a compound?
H
H-3
H2O
O-16
5. What do chemical symbols and formulas represent, respectively?
elements and compounds
atoms and mixtures
compounds and mixtures
elements and ions
Explanation:
83 km/h * 2.5 hours (3:30 - 1:00) = 207.5 km
207.5 km - 15 km = 192.5 km
As we know that block of steel is continue to be in moving state
so here the friction must be kinetic friction between two surface
so we know that formula of kinetic friction must be
now we have
now from the above equation we have
So here we need atleast 14.25 N force to continue sliding the box now as per given options all forces which are less than 14.25 N is not correct
Hence correct answer must be 18.0 N
<u>D) 18.0 N</u>
