Question

Tectonic plates are large segments of the Earth's crust that move slowly. Suppose that one such plate has an average speed of 4.0 cm/year. (a) What distance does it move in 1 s at this speed? (b) What is its speed in kilometers per million years?

Answer 1

Answer:

a) 1.268×10⁻⁷ cm/sec

b) 40 km/million years.

Explanation:

Speed of tectonic plate = 4.0 cm/year

a) Convert the year to seconds

1 year = 365 days × 24 hours × 60 minutes × 60 seconds

⇒1 year = 31536000 seconds

So,

$4\ cm/year = \frac{4}{31536000}\\\Rightarrow 4\ cm/year = \frac{1}{7884000}\\\Rightarrow 4\ cm/year = 1.268\times 10^{-7} cm/sec$

Distance plate will move in 1 second is 1.268×10⁻⁷ cm/sec

b) Convert cm to km

$4\ cm=\frac{4}{10^{-5}}\ km$

So, in 1 year it will move 0.00004 km

Hence in 1 million years is will move

0.00004 × 10⁶ = 40 km/million years.

Speed in kilometers per million years is 40 km/million years.