Questions: Multiple Choice
1 point
A scientist has discovered that the temperature in Kelvins of a layer in the earth's atmosphere can be given by T=300(2-0.01 ln (l)), where l is the height in kilometers of the layer to the ground. Find the temperature of a point which is 180 kilometers high. Round to the nearest tenth of a K .
-652.1 K
472.8 K
584.4K
45.3 K
Multiple Choice 1 point
Convert 50 feet to meters and centimeters.
14 m ; 11 cm
15 m ; 24 cm
11 m ; 2 cm
18 m ; 36 cm
Multiple Choice
1 point
In 2009, 80 frogs were introduced into a marsh. By 2015, the population had grown to 180 frogs. Write an algebraic function N(t) representing the population of frogs N over time t.
Transcript text: Multiple Choice
1 point
A scientist has discovered that the temperature in Kelvins of a layer in the earth's atmosphere can be given by $T=300(2-0.01 \ln (l))$, where l is the height in kilometers of the layer to the ground. Find the temperature of a point which is 180 kilometers high. Round to the nearest tenth of a K .
$-652.1 \mathrm{~K}$
472.8 K
584.4K
45.3 K
Multiple Choice 1 point
Convert 50 feet to meters and centimeters.
$14 \mathrm{~m} ; 11 \mathrm{~cm}$
$15 \mathrm{~m} ; 24 \mathrm{~cm}$
$11 \mathrm{~m} ; 2 \mathrm{~cm}$
$18 \mathrm{~m} ; 36 \mathrm{~cm}$
Multiple Choice
1 point
In 2009, 80 frogs were introduced into a marsh. By 2015, the population had grown to 180 frogs. Write an algebraic function $N(t)$ representing the population of frogs N over time t.
Solution
Solution Steps
Solution Approach
Temperature Calculation: To find the temperature at a height of 180 kilometers, substitute \( l = 180 \) into the given formula \( T = 300(2 - 0.01 \ln(l)) \) and compute the result. Round the result to the nearest tenth.
Conversion from Feet to Meters and Centimeters: Use the conversion factor where 1 foot equals 0.3048 meters. Convert 50 feet to meters, then separate the integer part as meters and convert the decimal part to centimeters.
Algebraic Function for Frog Population: Use the given data points (2009, 80) and (2015, 180) to determine a linear function \( N(t) \) that models the population over time. Calculate the slope and use the point-slope form to find the equation.
Step 1: Temperature Calculation
To find the temperature \( T \) at a height of \( l = 180 \) km, we use the formula:
\[
T = 300(2 - 0.01 \ln(l))
\]
Substituting \( l = 180 \):
\[
T = 300(2 - 0.01 \ln(180)) \approx 584.4 \, K
\]
Step 2: Conversion from Feet to Meters and Centimeters
To convert \( 50 \) feet to meters, we use the conversion factor \( 1 \, \text{foot} = 0.3048 \, \text{meters} \):
\[
\text{meters} = 50 \times 0.3048 \approx 15.24 \, \text{m}
\]
Separating the integer part gives \( 15 \, \text{m} \) and converting the decimal part to centimeters:
\[
\text{centimeters} = (0.24 \, \text{m}) \times 100 \approx 24 \, \text{cm}
\]
Step 3: Algebraic Function for Frog Population
Using the data points \( (2009, 80) \) and \( (2015, 180) \), we calculate the slope \( m \):
\[
m = \frac{180 - 80}{2015 - 2009} = \frac{100}{6} \approx 16.67
\]
The population function \( N(t) \) can be expressed as:
\[
N(t) = 16.67(t - 2009) + 80
\]
For \( t = 2010 \):
\[
N(2010) \approx 96.67
\]
Final Answer
The results are as follows:
Temperature at \( 180 \) km: \( \boxed{584.4 \, K} \)
Conversion of \( 50 \) feet: \( \boxed{15 \, m; \, 24 \, cm} \)
Estimated population in \( 2010 \): \( \boxed{96.67} \) frogs