Final answer:
The average speed of Earth in its orbit around the Sun is approximately 29.8 km/s, which is converted to 30 km/s for the multiple choice options provided. This speed can also be expressed as 29,800 m/s.
Step-by-step explanation:
To calculate Earth’s average speed relative to the Sun, we refer to the average distance between Earth and the Sun, which is 1.5 × 1011 meters. By assuming the orbit to be circular, we can calculate the circumference of Earth's orbit using the formula 2πR (where R is the radius). Thus, the circumference is 2π × 1.5 × 1011 meters. The Earth takes one year to complete this orbit. Since one year is equal to 3.156 × 107 seconds, we can calculate the speed by dividing the circumference by the orbital period in seconds. The average speed of Earth around the Sun is therefore 29.8 km/s, which corresponds to the answer option A. 30 km/s.
The speed in meters per second (m/s) can be found by multiplying by 1,000, as there are 1,000 meters in a kilometer, resulting in an average speed of 29,800 m/s.