Some runners have just started a race. They began at rest and are getting faster. What statement best describes the motion of the runners at the beginning of the race (right after they start running)? A. Acceleration and speed both remain constant.
B. Velocity and speed both remain constant.
C. Acceleration is positive and speed is increasing.
D. Velocity remains the same and speed is positive

The volumes of a sample of lead and a sample of platinum are the same: 2 cm3. the density of lead is 11.3 g/cm3 and the density of platinum is 21.5 g/cm3. which is an accurate description of their relative masses? a. the masses of the lead and platinum samples are the same. b. the mass of the lead sample is greater than the mass of the platinum sample. c. the mass of the platinum sample is greater than the mass of the lead sample.