A lion's heart beats 12 times in 16 s. How many times does a lion's heart beat in 60 s?

$$F. \ 24 \\ G. \ 32 \\ H. \ 45 \\ J. \ 192$$

The function $P(t)=145 e^{-0.092 t}$ models a runner's pulse, $P(t)$, in beats per minute, $t$ minutes after a race, where $0 \leq t \leq 15$. Graph the function using a graphing utility. $\boxed{\text{TRACE}}$ along the graph and determine after how many minutes the runner's pulse will be $70$ beats per minute. Round to the nearest tenth of a minute. Verify your observation algebraically.

Recommended heart rates during exercise vary with age and physical condition. For a healthy person doing moderate to intense exercise, such as hiking. the inequality

$$0.5 ( 220 - a ) \leq R \leq 0.9 ( 220 - a )$$

gives a target range for the heart rate R (in beats per minute), based on age a (in years). a. What is the target range for heart rates for a person 15 years old? b. How old is a person whose target range is between 99 and 178.2 beats per minute?

"To tune your violin, you first tune the A string to the correct pitch of $440 \text{~Hz}$, and then you bow both it and an adjoining string simultaneously, all the while listening for beats. While bowing the A and E strings, you hear a beat frequency of $3.00 \text{~Hz}$ and note that the beat frequency increases as the tension on the E string are increased. (The E string is to be tuned to $660 \text{~Hz}$.) $(a)$ Why are beats produced by these two strings when bowed simultaneously?"

A hummingbird in flight beats its wings at a rate of 70 times per second. How many times does it beat its wings in an hour if it is in flight 70% of the time?

Recommended heart rates during exercise vary with age and physical condition. For a healthy person doing moderate to intense exercise, such as hiking, the inequality $0.5(220-a) \leq R \leq 0.9(220-a)$ gives a target range for the heart rate R (in beats per minute), based on age a (in years). a. What is the target range for heart rates for a person 15 years old? b. How old is a person whose target range is between 99 and 178.2 beats per minute?

To play a $\mathrm{C}$ major chord on the piano, you hit the $\mathrm{C}, \mathrm{E}$, and $\mathrm{G}$ keys simultaneously. When you do so, you hear no beats. Why?

A dragonfly can beat its wings 30 times per second. Write an equation in slope-intercept form that shows the relationship between flying time in seconds and the number of times the dragonfly beats its wings. _

A police siren contains two frequencies, producing a wavering sound (beats). Explain how the siren sound changes as a police car approaches, passes, and moves away from a pedestrian.

A dragonfly can beat its wings 30 times per second. Write an equation in slope-intercept form that shows the relationship between flying time in seconds and the number of times the dragonfly beats its wings.

A piano tuner listens to a tuning fork vibrating at 440 Hz to tune the string of a piano. He hears beats between the tuning fork and the piano string. Is the string in tune? Explain your answer.

Two tuning forks are producing sounds of wavelength $34.40 \mathrm{~cm}$ and $33.94 \mathrm{~cm}$ simultaneously. How many beats do you hear each second?

Flight Characteristics "

$$\begin{matrix} \text{Type of Insect} & \text{Wing Beats (per second)} & \text{Flight Speed (kilometers per hour)}\\ \text{Hummingbird moth} & \text{85} & \text{17.8}\\ \text{Bumblebee} & \text{250} & \text{10.3}\\ \text{Housefly} & \text{190} & \text{7.1}\\ \end{matrix}$$

" -Based on the data, is there a relationship between the rate at which an insect beats its wings and the speed at which it flies? Explain. What factors besides wing-beat rate might affect flight speed?

In 20 minutes, how many more times does a gerbil's heart beat than a rabbit's?