Question

Simplify the expression. Write the answer using scientific notation.

Astronomers measure large distances in light-years. One light-year is the distance that light can travel in one year, or approximately 5,880,000,000,000 miles. Suppose a star is 15.8 light-years from Earth. In scientific notation, how many miles away is it?

Answer 1

we are given with two distances: 5,880,000,000,000 miles and 15.8 light-years. we convert first the light-years distance through the speed of light : 3 x 108 m/s. v = d/t; d = 3x10 8 m/s * 15.8 light years * 31536000 s = 1.4948 x1017 m = 9.28829 x 1013 miles. The difference thus is 8.70029 x 1013 miles