The average density of the material from which the coin is made is 9.67 g/cm³.
<h3>Volume of the coin</h3>
The volume of the coin at the given diameter is calculated as follows;
V = Ah
where;
- A is area of the coin
- h is the thickness of the coin
V = πd²/4 x h
V = π(2.8)²/4 x (0.21 cm)
V = 1.293 cm³
<h3>average density of the coin</h3>
The average density of the material from which the coin is made is calculated as follows;
density = mass/volume
density = 12.5 g / (1.293 cm³)
density = 9.67 g/cm³
Thus, the average density of the material from which the coin is made is 9.67 g/cm³.
Learn more about average density here: brainly.com/question/1354972
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A) Agreed.
<span>b) Value agreed but units should be W (watts). </span>
<span>c) Here's one method... </span>
<span>15 miles = 24140 m </span>
<span>1 gallon of gasoline contains 1.4×10⁸ J. </span>
<span>So moving a distance of 24140m requires gasoline containing 1.4×10⁸ J </span>
<span>Therefore moving a distance of 1m requires gasoline containing 1.4×10⁸/24140 = 5800 J </span>
<span>Overcoming rolling resitance for 1m requires (useful) work = force x distance = 1000x1 = 1000J </span>
<span>So 5800J (in the gasoline) provides 1000J (overcoming rolling resistance) of useful work for each metre moved. </span>
<span>Efficiency = useful work/total energy supplied </span>
<span>= 1000/5800 </span>
<span>= 0.17 (=17%) </span>
Answer:
c. selenium
Explanation:
sulfur and selenium are in the same group
Answer: B
Explanation:
It's not the time it took to heat the substance, so that rules out A and C.
This means that we only have to choose between
B. the area of contact
D. the area of the substances
(since everything else in each of those answers are the same)
Area of contact matters more (e.g. an object with greater surface area is exposed to the air more, will lose/gain heat quicker than an object with less surface area).
