Solve each problem. Simple InterestSimple interest varies jointly as principal and time. If \$1000 invested for 2 yr earned \$70, find the amount of interest earned by \$5000 invested for 5 yr.
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- 4. Polynomial Functions1h 44m
- 5. Rational Functions1h 23m
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1. Equations & Inequalities
Rational Equations
Problem 50
Textbook Question
Solve each problem. Nuclear Bomb DetonationSuppose the effects of detonating a nuclear bomb will be felt over a distance from the point of detonation that is directly proportional to the cube root of the yield of the bomb. Suppose a 100-kiloton bomb has certain effects to a radius of 3 km from the point of detonation. Find, to the nearest tenth, the dis-tance over which the effects would be felt for a 1500-kiloton bomb.
Verified step by step guidance1
Identify the relationship given: the distance over which effects are felt, \(d\), is directly proportional to the cube root of the yield, \(y\). This can be written as \(d = k \sqrt[3]{y}\), where \(k\) is the constant of proportionality.
Use the information about the 100-kiloton bomb to find \(k\). Substitute \(d = 3\) km and \(y = 100\) into the equation: \$3 = k \sqrt[3]{100}$.
Solve for \(k\) by dividing both sides by \(\sqrt[3]{100}\): \(k = \frac{3}{\sqrt[3]{100}}\).
Now use the value of \(k\) to find the distance for the 1500-kiloton bomb. Substitute \(y = 1500\) into the original formula: \(d = k \sqrt[3]{1500}\).
Replace \(k\) with the expression found in step 3 to get \(d = \frac{3}{\sqrt[3]{100}} \times \sqrt[3]{1500}\). Simplify this expression to find the distance, then round to the nearest tenth.
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Key Concepts
Here are the essential concepts you must grasp in order to answer the question correctly.
Direct Proportionality
Direct proportionality means one quantity changes at a constant rate relative to another. If distance is directly proportional to the cube root of the yield, then distance = k × (yield)^(1/3), where k is a constant. Understanding this relationship helps set up the equation to find unknown distances.
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Cube Root Function
The cube root function, denoted as ∛x, is the inverse of cubing a number. It extracts the value that, when cubed, returns x. In this problem, the distance depends on the cube root of the bomb's yield, so calculating cube roots accurately is essential.
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Solving for a Constant of Proportionality
To use direct proportionality, first find the constant k by substituting known values into the formula. Here, use the 100-kiloton bomb data to find k, then apply k to find the distance for the 1500-kiloton bomb. This step is crucial for solving the problem correctly.
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