# College Physics Problem 2.7

#### The North American and European continents are moving apart at a rate of about 3 cm/y. At this rate how long will it take them to drift 500 km farther apart than they are at present?

SOLUTION:

We know that the formula for velocity is

If we rearrange the formula and solve for time, we come up with

Substituting the given values,

$\Delta t=\frac{500\ km}{3\ cm/year}=\frac{5\times 10^{5}\ m}{3\ cm/yr}\times \frac{100\ cm}{1\ m} =1.67 \times 10^{7}\ years$

Therefore, the time it will take is about $1.67\times 10^{7}\ years$.