The mean distance of Earth from the Sun is 9.29 x 10^7 miles. Assuming that the orbit of Earth around the Sun is circular and that 1 revolution takes 365 days, find the linear speed of Earth. Express your answer in miles per hour.
You have missed out the part that says "with respect to a reference frame at rest with respect to the sun".
Circumference of orbit $\displaystyle C=2 \times \pi \times 9.29 \times 10^7$
Period in hours: $\displaystyle \tau=365 \times 24$
Speed in miles per hour $\displaystyle =C/\tau$
RonL