Solution:

1. A bird is flying due east. Its distance from a tall building is given by x(t) = 28.0 m + (12.4 m/s)t - (0.0450 m/s^3)t^3. What is the instantaneous velocity of the bird when t = 8.00 s?

2. The density of gold is 19.3 grams per cubic meter. What is this value in kilograms per cubic meter?