# Physics

I must show my work for full credit. I need help on this question. I don't need answers, but could you help me figure it out.
Thanks

A microbiologist measures the speed of a swimming bacterium. The bacterium covers a distance of 2.16 microns in 5.0 seconds. The biologist wished to compare the speed of the bacteria with other animals, but the speeds of other animals are listed in kilometers per hour. What is the speed of the bacterium in kilometers per hour? (1 micron = 1 x 10–6 m) Use scientific notation and express your answer to the correct number of significant figures.

1. 👍 0
2. 👎 0
3. 👁 363
1. You are not understanding the factor label method using unit factors.
Note these
1micron=1E=6 m
or 1 = 1E-6 m/micron=1micron/1E-6 m
notice that is a unity factor (equal to 1)
also note
1000m=1km or
1=1km/1000m = 1000m/1km
Now, because you can multiply anything in an equation by ONE... then
speed=distance/time=2.16microns/5 seconds

now, we start multiplying by UNIT factors to divide out the units. Starting with the microns in the numerator..
speed=2.16microns/5s * 1E-6m/micron
microns divides out, now you have left meters/second
then, multiply to get the meters do change to km. Multiply by 1km/1000m
so now the units are meters/second.

Now, seconds to hours. 3600s=1hr or
1=1hr/3600s= 3600s/hr

because you have seconds in the denominator, you want to multply speed you have in km/s by (3600s/hr)

and you are done. The trick is to write this down, with the UNITS attached, so you see they do in fact cancel. You cant use a calculator to do this. So wait until you have got the units where you need them, then get the calc. Then you should have this...

(2.16/5)(1e-6/1)(1/1000)(3600/1) CHECK THAT.

1. 👍 0
2. 👎 0
👨‍🏫
bobpursley
2. Thanks, I was not really understanding the factor label method until now, this helped out a lot. I appreciate it.

1. 👍 0
2. 👎 0

## Similar Questions

1. ### Math

A store buys 77 1/2 pounds of mulch in a large shipment. They divide the mulch up into bags that can each hold 2 1/4 pounds. The store sells one bag of mulch for \$2.25. for each part of the question, show your work. a. How many

2. ### Trig

Find the point on the terminal side of θ = three pi divided by four that has a y coordinate of 1. Show your work for full credit.

3. ### geometry

M is the midpoint of segment AB, AM=2x+4 and AB=12x+4. What is the value of MB? Show your work for credit.

4. ### chemistry

A nitrogen atom has 7 protons, and its most common isotope has 7 neutrons. A radioactive isotope of nitrogen has 9 neutrons. What is the atomic number and what is the mass number of this radioactive nitrogen? Show all of your work

1. ### Statistics

At 100 college campuses, 1200 full-time undergraduate students were surveyed on their credit card usage. Among juniors, 65% reported that they didn't have a credit card in their own name, and 23% reported that they had at least

2. ### geometry

An observatory has the shape of a right circular cylinder topped by a hemisphere. The radius of the cylinder is 8 ft and its altitude measures 26 ft What is the approximate surface area of the observatory? Round to the nearest

3. ### Science

Really confused on this question. A microbiologist measures the speed of a swimming bacterium. The bacterium covers a distance of 2.16 microns in 5.0 seconds. The biologist wished to compare the speed of the bacteria with other

4. ### help!!!!!!!! Physics

A microbiologist measures the speed of a swimming bacterium. The bacterium covers a distance of 2.16 microns in 5.0 seconds. The biologist wished to compare the speed of the bacteria with other animals, but the speeds of other

1. ### geometry

M is the midpoint of Symbol for Segment A B.. Find the coordinates of B given A(7,-2) and M(10,10). Show your work for credit

2. ### Calculus

The percentage of the moon's surface that is visible to a person standing on the Earth varies with the time since the moon was full. The moon passes through a full cycle in 28 days, from full moon to full moon. The maximum

3. ### question

David has a company decorating houses for the holidays. He has secured a \$25,000 line of credit from his bank. For which purpose is David more likely to use this credit line? Question 19 options: a warehouse to store decorations

4. ### math

Write the equation of the line that passes through the points (4, 7) and (-3, 7). Show all your work for credit.