## anonymous one year ago Suppose Galileo and his assistant were 1 km apart when Galileo uncovered his lantern to try to measure the speed of light. How long would it have taken the light signal to reach his assistant? A. 3.0 * 10^8 s B. 3.3 * 10^-9 s C. 1.0 s D. 3.3 * 10^-6 s

1. Michele_Laino

it is simple, since we have to apply this formula: $t = \frac{d}{c} = \frac{{10 \times 3}}{{3 \times {{10}^8}}}$

2. Michele_Laino

oops..I have made a typo, here is the right formula:

3. anonymous

ok!

4. Michele_Laino

$t = \frac{d}{c} = \frac{{{{10}^3}}}{{3 \times {{10}^8}}}$

5. anonymous

we get 3.333333333E-6?

6. Michele_Laino

yes!

7. anonymous

so our solution is choice D?

8. Michele_Laino

yes!

9. anonymous

yay!! :) Thanks!!

10. Michele_Laino

:)