Annika is on the track team and competes in the 800 meter event. In a recent race, she ran two complete laps around a conventional oblong 400-meter track in 2 minutes 54.0 seconds.

a) What was her average speed for the entire race?

b) What was her average velocity for the entire race?

2) Can any object have acceleration in a direction opposite to its velocity? If so, give two examples.

5) The tires of a car begin to lose traction on the road at an acceleration of 5.0 meters/second2. At this acceleration how long does it take the car to increase its speed from 5.0 m/s to 25 m/s?

6) A boy at a national park leans over a guardrail at the top of a canyon wall and (illegally) drops a stone onto the canyon floor far below. The stone hits the canyon floor 9.0 seconds later. The canyon wall is a sheer vertical wall. You may neglect air resistance in this problem.

a) What is the height of the guardrail above the canyon floor?

b) What was the ball's speed just before it hit the canyon floor?

c) If the boy had thrown the stone from the same position by the guardrail with an initial velocity of 3.0 meters/second in a horizontal direction, how long would the stone have fallen until it hit the canyon floor?

7) Bill points his rowboat directly across a river and rows at a speed of 1.2km/hour, but the river's current flows with a velocity of 2.0km/hr downstream. The river is 1.8km wide.

a) How long will it take Bill to cross the river?

b) How far downstream will Bill land?

8) Erik threw a baseball vertically upward and caught it 2.5 seconds later. You may neglect air resistance in this problem.

a) What was the initial speed with which he threw the ball?

b) What was the maximum height that the ball attained?