*100 points, do all if not most of the questions listed, you*
dimensional analysis
1a. (25km/5)(1000m/1km)(1h/3600s) =
carry out the following conversions using the factor-label method. show all of your work !
2a. how many seconds are in a year?
2b. convert 28km to cm
2c. convert 45kg to mg
2d. convert 85cm/min to m/s
2e. convert the speed of light, 3x10^8 to km/day
2f. convert 823nm to m
2g. 8.5cm^3 to m^3

What are the phases shown in a and d called?

Why is it important always to use horizontal bars in unit fractions when performing unit conversions?

When a vertical beam of light passes through a transparent medium, the rate at which its intensity i decreases is proportional to i(t), where t represents the thickness of the medium (in feet). in clear seawater, the intensity 3 feet below the surface is 25% of the initial intensity i0 of the incident beam. what is the intensity of the beam "10" feet below the surface? (give your answer in terms of i0. round any constants or coefficients to five decimal places.)