27. CHALLENGE The car in Figure 16 travels west with a forward acceleration of 0.22 m/s2. What was the car's velocity (v) at point x if it travels a distance of 350 m in 18.4 s? Vi = ? x x Figure 16

A60-gram sample of radioactive isotope is measured after two half-lives have passed. what pair of percentages describe the sample after two-half lives? a.) 50% unchanged and 50% stable b.) 25% unchanged and 75% stable c.) 12.5% unchanged and 87.5% stable d.) 75% unchanged and 25% stable