Explanation:
It is given that,
The North American and European plates of the Earth’s crust are drifting apart with a relative speed of about, v = 25 mm/ yr
We know that, \(1\ mm/yr=3.171\times 10^{-11}\ m/s\)
\(v=7.927\times 10^{-10}\ m/s\)
Distance between them, \(d=2.9\times 10^3\ mi\)
1 mile = 1609.34 meters
\(d=2.9\times 10^3\ mi=4667098\ m\)
Let t is the time when the rift between them started to open. Speed is given by distance travelled divided by time taken.
\(t=\dfrac{d}{v}\)
\(t=\dfrac{4667098\ m}{7.927\times 10^{-10}\ m/s}\)
\(t=5.88\times 10^{15}\ s\)
Since, \(1\ s=3.17\times 10^{-8}\ yr\)
So, \(t=18.63\times 10^7\ years\)
or
t = 1.86 million years
Hence, this is the required solution.
