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# yea im back

+3
1485
4
+470

and i may need mathematics assistance later in the year

off-topic
Oct 19, 2017

#1
+450
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Ok, shoot, and I will see what I can do for you. (I am certified to tutor math for Kindergarten- 4th grade.) But I do enjoy higher grade math challenges!

Oct 19, 2017
#2
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"The mass of a dust particle is approximately 7.5x10^-10 kilograms and the mass of an electron is 9.1x10^-31 kilograms. Approximately how many electrons have the same mass as one dust particle?"

(X stands for multiplication in this case)

Neptune  Oct 19, 2017
#3
+2

(7.5 x 10^-10) / (9.1 x 10-31) =8.24 x 10^20 electrons in 1 mote of dust.

Oct 19, 2017
#4
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"The mass of a dust particle is approximately 7.5x10^-10 kilograms

and the mass of an electron is 9.1x10^-31 kilograms.

Approximately how many electrons have the same mass as one dust particle?"

This is just a division problem. You want electrons are in each dust particle

So how many times 9.1x10^-31 kilograms. goes into 7.5x10^-10 kilograms

7.5x10^-10 kilograms      divided by     9.1x10^-31 kilograms

(7.5x10^-10) / (9.1x10^-31)

=(7.5/9.1) * (10^-10 / 10^-31) electrons per particle

(7.5/9.1) = 0.8241758241758242 = 8.241758241758242*10^-1

(10^-10 / 10^-31) = 10^21

$$\approx 8.24\times 10^{-1}\times 10^{21}\\ \approx 8.24\times 10^{20}\;\;\text {electons in one dust particle}$$