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:
Answer
Given,
Energy absorbed, 
Energy expels,
Temperature of cold reservoir, T = 27°C
a) Efficiency of engine
b) Work done by the engine
c) Power output
t = 0.296 s
My answers would be as follows:
<span>You step on the scale and notice that you have lost five pounds. Which of the following has changed?
B) Only your weight changed since mass is conserved. It cannot be destroyed or created.
How could you increase the mass of a wooden block?
D) None of the above. Mass cannot be created so the mass will stay the same it will only be the weight you can increase depending on the acceleration.
If you went to the moon, how would your mass change relative to your mass on Earth?
A) It would be the same on the moon as on Earth. Mass will be the same. It is weight that will change since the gravitational acceleration in the moon is different as that to the earth.
</span>
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Answer:
19.8 J
Explanation:
According to the law of conservation of energy, the total mechanical energy of the spring (sum of kinetic energy and elastic potential energy) must be conserved:
(1)
where we have
is the initial kinetic energy of the spring, which is zero because the spring starts from rest (2)
is the elastic potential energy of the spring when it is fully stretched
is the kinetic energy of the spring when it reaches the natural length
is the elastic potential energy of the spring when it reaches its natural length, which is zero because the stretch in this case is zero (3)
So
where
k = 440 N/m is the spring constant
is the initial stretching of the spring
Substituting,
And so using eq.(1) and keeping in mind (2) and (3) we find
