Physics

posted by .

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.

  • Physics -

    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.

  • Physics -

    Thanks, I was not really understanding the factor label method until now, this helped out a lot. I appreciate it.

Respond to this Question

First Name
School Subject
Your Answer

Similar Questions

  1. geometry

    <DEF and <ABC are supplementary angles and <DEF is seven times as large as <ABC. Determine the measures of each angle. Students must show all work step by step to receive full credit.
  2. math

    Find the perimeter and area of a right triangle if one leg measures 9 cm and the other leg measures 40 cm. Students must show all work step by step to receive full credit for the problem. Include correct units with your solution.
  3. chemistry

    This question I really don't get it. I tried tried tried to figure out how to start solve the problem but still couldn't figure out. So can you help me with one question PLEASE?
  4. Physic

    You must show your work for full credit.) Calculate the average speed of an oxygen molecule (with a mass of 5.3e-26 kg) at room temperature (300 Kelvin):
  5. Physics

    :'( Please help me....? (7 points) 2. Contrast the metric units of distance, time, and speed. Describe the relationship between them. Answer: (11 points) 3. A microbiologist measures the speed of a swimming bacterium. The bacterium
  6. Complex Algaebra, Plz Help!!

    Good evening to all around the world. Need help with this question, however i must show my answers supported by the working out. Please help. This question is difficult, the one who solves it for me is my hero!!!! Q11) Two functions …
  7. 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 animals, …
  8. 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 animals …
  9. physics

    You must show your work for full credit.) Calculate the circular speed of an object that orbits the Sun at a distance of 0.2 AU (1 AU = 1.5e+11 meters, the distance between the Earth and the Sun)
  10. Geometry

    A carpenter is building a staircase using his knowledge of right angles. The steps have a horizontal landing and a vertical rise causing each step to be a right triangle cut out. Depending on the purpose, steps may be adjusted by the …

More Similar Questions