Answer
a) 2.99 x $10^{4}$ m/s
b) a) 2.69 x $10^{4}$ m/s
Work Step by Step
a) Distance
= $\frac{2\pi\times r}{4}$
= $\frac{2\pi\times 1.50 \times 10^{11}}{4}$
$\approx$ 2.3562 x $10^{11}$ m
Average speed
= $\frac{2.3562 \times 10^{11}}{7.89 \times 10^{6}}$
$\approx$ 2.99 x $10^{4}$ m/s
b) displacement
= $\sqrt 2 \times (1.50 \times 10^{11})^{2}$
$\approx$ 2.1213 m
Average velocty
= $\frac{2.1213 \times 10^{11}}{7.89 \times 10^{6}}$
$\approx$ 2.69 x $10^{4}$ m/s