Exponential growth & decay with logs - application problems

Find the pH of a solution that has a hydrogen ion concentration of 0.000 000 004 9.

• 1.0

• 4.9

• 6.1

• 8.3

The relative intensity of a car's engine is 76 dB. What is it in W/m²?

• 2.51x10^-8

• 3.98x10^-5

• 138.81

• 39810717.06

A radioactive element has a decay constant of -0.000 120 968 /yr. What element is it?

• Carbon-14

• Radium-226

• Plutonium-239

• Cobalt-60

I have a 500 gram sample of cobalt-60. How many years until I only have 320 grams left? (the decay constant is -0.131 526 98/yr)

• 3.4 years

• 1.6

• 2.6

• 5.9

What is the hydrogen ion concentration of an aspirin if it has a pH of 2.6?

• 398.1

• 0.415

• 0.0025

• 0.089

You whisper with an intensity of 0.000 000 000 3 W/m². How many decibels is that?

• 20.1

• 22.4

• 24.8

• 26.3

What element takes 52096412.7 years for 2 grams to decay to 1.9 grams? (hint: find the decay constant first, then use it to find its half life).

• Potassium-40

• Uranium-235

• Carbon-14

• Plutonium-239

Mr. Lukosavich makes an announcement over the P.A. using an 85 dB voice. What is the intensity, in W/m², of his voice?

• 0.000316

• 3.16

• 10^3.16

• 0.0316

If all other factors are equal, the higher the displacement D in liters of the air/fuel mixture of an engine, the more horsepower H is will produce. The horsepower of a naturally aspirated engine can be modeled by the formula in figure 2. Find the displacement when the horsepower is 350.

• 2.871 liters

• 1.983 liters

• 3.977 liters

• 4.578 liters

The number of miles d of roads cleared of snow is modeled by the formula in figure 3. Find the number of miles cleared when the snow is 10 inches high.

• 25.3 miles

• 27.2 miles

• 29.1 miles

• 32.4 miles