Question

1)Two boats start together and race across a 48-km-wide lake and back. Boat A goes across at 48 km/h and returns at 48 km/h. Boat B goes across at 24 km/h, and its crew, realizing how far behind it is getting, returns at 72 km/h. Turnaround times are negligible, and the boat that completes the round trip first wins. A) By how much? B)What is the average velocity of the winning boat?

2)A race car moves such that its position fits the relationship x = (5.5 m/s)t + (0.60 m/s3)t3 where x is measured in meters and t in seconds. A)Determine the instantaneous velocity of the car at t = 5.0 s, using time intervals of 0.40 s, 0.20 s, and 0.10 s. (In order to better see the limiting process keep at least three decimal places in your answer.) Δt = 0.40 s m/s (Use the interval from t = 4.80 s to 5.20 s.) Δt = 0.20 s m/s (Use the interval from t = 4.90 s to 5.10 s.) Δt = 0.10 s m/s (Use the interval from t = 4.95 s to 5.05 s.)

Answer 1