Final answer:
Earth's tectonic plates move approximately 2 inches each year. This rate, converted to metric, is about 5 cm per year, corresponding to the average motion for tectonic plates. Additional calculations show that a plate moves 1.3 × 10^-9 meters per second and has a speed of 4.0 × 10^1 kilometers per million years.
Step-by-step explanation:
The question pertains to the movement of Earth's tectonic plates and their rate of motion relative to a given time period. Tectonic plates comprise the outer crust of the Earth and are known to move incrementally over time due to convective currents in the mantle beneath them. This motion is quantified in terms of centimeters per year. References to plate tectonics often compare this speed to the rate at which human hair grows, indicating how slow the process is.
The correct answer to the student's question is: 'Earth's plates move approximately 2 inches each year.' When we convert inches to centimeters, we find that 2 inches is roughly equivalent to 5 centimeters, which aligns with the average speed of 4 to 5 centimeters per year mentioned in the reference material provided.
To address the additional questions provided: (a) If a tectonic plate moves at 4.0 cm/year, then the distance moved in 1.0 second would be calculated by converting the yearly distance into a per second value. This involves dividing the yearly distance by the number of seconds in a year (31,536,000 seconds). Using this method,
4.0 cm/year becomes approximately 1.3 × 10-9 meters per second (since 1 cm equals 0.01 meters). (b) To find the speed in kilometers per million years, we convert the speed from centimeters per year to kilometers per million years by multiplying 4.0 cm/year by 105 to get kilometers and by 106 to scale to a million years, resulting in 4.0 × 101 kilometers per million years.