1. A person walks first at a constant speed of 5.23 m/s along a straight line from point A to point B and then back along the line from B to A at a constant speed of 3.10 m/s. (a) What is the average speed over the entire trip? (b)What is the average velocity over the entire trip?
2. On your wedding day your lover gives you a gold ring of mass 3.86 g. 53 years later its mass is 3.17 g. On the average how many atoms were abrated from the ring during each second of your marriage? The atomic mass of gold is 197 u.
3. A tortoise can run with a speed of 10.8 cm/s, and a hare can run 20.7 times as fast. In a race, they both start at the same time, but the hare stops to rest for 115 seconds. The tortoise wins by a shell (19.4 cm). (a) How long does the race take? (b)What is the length of the race?
4. A driver in a car traveling at a speed of 62.2 mi/h sees a deer 115 m away on the road. Calculate the minimum constant acceleration that is necessary for the car to stop without hitting the deer (assuming that the deer does not move in the meantime).
5. A jet plane lands with a velocity of +115 m/s and can accelerate at a maximum rate of -4.84 m/s2 as it comes to rest. (a) From the instant it touches the runway, what is the minimum time needed before it can come to rest? (b) Can this plane land on a small tropical island airport where the runway is 1296.13 m long?
Tags: