Question

Assuming biological substances are 90 percent water and the density of water is 1.0 x 10^3 kg/m^3, estimate the masses (density multiplied by volume) of the following.

a. a spherical cell with a diameter of 1.0 um (volume = 4/3 pi r^3

b. a fly, which can be approximated by a cylinder 4.0 mm long and 2.0 mm in diameter (volume = lpir^2

Answer 1

what do u mean by 1.0 um...

Answer 2

It means 10^-6 m like how cm is 10^-2 m

Answer 3

ok hold on

Answer 4

ok

Answer 5

mass of water in (a)

mass of water = 1000kg/m^3

radius of sphere = 0.5 x 10^-6 m

\[V = \frac{ 4 }{ 3 } \pi r^3 \]
substituting, values of r, then you'll get 5.236 x 10^-19 m^3

Hence weight of water in that sphere is 5.236 x 10^-19 x 1000 = 5.236 x 10^-16 kg

Answer 6

hold on.. solving b

Answer 7

kk

Answer 8

same goes..
radius is 10^-3 m
\[V= \pi r^2 l \]

then substituting values of r and l then you'll get 1.2566 x 10^-8 m^3

multiplying with 1000 then you get 1.2566 x 10^-5 kg. or can be simplified to 12.57 microgram (correct to 4 s.f.)

Answer 9

solved

Answer 10

ok let me check it really fast. Thanks for the help

Answer 11

I got 12566 for some reason

Answer 12

thats 5 signifiant figures. mine i rounded it to 4

Answer 13

ok

Answer 14

also do you mind helping me out with one more problem hahaha :)

Answer 15

ok o.o btw vote me best response xD

Answer 16

I WILL BE HAPPY TO DO IT AGAIN :)

Answer 17

haha
posted your qst?

Answer 18

http://openstudy.com/study#/updates/52161a9ee4b00ebc7dc09494

Answer 19

So what is the units for both of the answers. Kg or m^3 also I got 1.25 x 10^-2 kg

Answer 20

I got 1.25 times 10^-2 mkg

Answer 21

?

Answer 22

hmm my aswer here i recalculated still its 1.2566 x 10^-5 kg

Answer 23

in standard form kg

Answer 24

thats weird

Answer 25

I did pi (0.002/2)^2 (4)

Answer 26

i just did diameter over 2 instead of using radius

Answer 27

I do get 1.257 x 10^-5 for m^2 for volume?

Answer 28

u cant use diameter, you need to use radius...

Answer 29

ok just solve it step by step and show me what you did

Answer 30

then I sware to let you go :)

Answer 31

radius is 10^-3 m
length 4.0 x10^-3 m

V = pi (10^-3)^2 (4.0 x10^-3)
= 1.2566 x 10^-8
multiply 1000 = 1.2566 x 10^-5 kg

Answer 32

i forgot the length. Now i will try it out lol

Answer 33

lol......

Answer 34

I get the same answer but isn't it meters(kg) in units

Answer 35

?

Answer 36

lol i gtg d sry ><

Answer 37

can you look into it please?