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Not sure if you're allowed to ask multiple questions on here at once, but somebody please explain all of this to me.

Not sure if you're allowed to ask multiple questions on here at once, but somebody-example-1
User Aleksandr Sakharov
by
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1 Answer

4 votes
4 votes

1. First, convert the model distance to base SI.


30\,\mathrm{cm} = 3*10^(-1)\,\mathrm m

Then the ratio of model distance to actual distance is


(30\,\rm cm)/(1.50*10^(11)\,\rm m) = (3*10^(-1)\,\mathrm m)/(1.50*10^(11)\,\rm m) = (2)/(10^(12)) = (2)/(2*5*10^(11)) = (1)/(5*10^(11))

or 1 : 5 × 10¹¹.

2. The model/actual distance ratio should be the same for each planet.

Mercury:


12.6\,\mathrm{cm} = 1.26*10^(-1)\,\mathrm m


(12.6\,\rm cm)/(5.80*10^(10)\,\rm m) = (1.26*10^(-1)\,\rm m)/(5.80*10^(10)\,\rm m) \approx (1)/(4.6*10^(11))

or 1 : 4.6 × 10¹¹.

Venus:


21.6\,\mathrm{cm} = 2.16*10^(-1)\,\rm m


(21.6\,\rm cm)/(1.08*10^(11)\,\rm m) = (2.16*10^(-1)\,\rm m)/(1.08*10^(11)\,\rm m) = (2)/(10^(12)) = (2)/(2*5*10^(11)) = \frac1{5*10^(11)}

or 1 : 5 × 10¹¹.

Mercury's distance is the incorrect one. The correct model distance should be
x such that


(x\,\rm cm)/(5.80*10^(10)\,\rm m) = (1)/(5*10^(11))

Solve for
x.


x\,\mathrm{cm} = (5.80*10^(10)\,\rm m)/(5*10^(11))


x\,\mathrm{cm} = (1.16\,\rm m)/(10^1)


x\,\mathrm{cm} = 1.16*10^(-1)\,\rm m


x\,\mathrm{cm} = \boxed{11.6\,\rm cm}

3.The actual distance for Mars is
y such that


(34.4\,\rm cm)/(y\,\rm m) = (1)/(5*10^(11))

Solve for
y.


34.4*5*10^(11) \,\mathrm{cm} = y\,\rm m


y\,\mathrm m = 172 *10^(11)\,\rm cm


y\,\mathrm m = 172 *10^(13)\,\rm m


y\,\mathrm m = \boxed{1.72} *10^{\boxed{11}}\,\rm m

4. Divide the distance by the speed of light to recover the time.


(7.92*10^(11)\,\rm m)/(3.0*10^8(\rm m)/(\rm s)) = 2.64*10^3\,\mathrm s

Convert to minutes.


2.64*10^3\,\mathrm s \cdot (1\,\rm min)/(60\,\rm s) = 0.044*10^3\,\mathrm{min} = \boxed{44}\,\rm min

User Lavrik
by
3.3k points