1/19/10

Post date: Jan 19, 2010 1:20:25 AM

Bell Ringer: Compare and contrast speed and velocity.

• • Answer one another's test-like problems - due in class

  • Review material for tomorrow's test

    • Significant Digits

    • Scientific Notation

    • Factor-label

    • Calculations with v = d/t

    • distance vs. time graphs (finding distance or finding velocity with slope)

    • velocity vs. time graphs (finding velocity or finding displacement with area under the curve)

  • Review Jeopardy

  • Review problems for test (not to be turned in)

    • Chapter 3 End-of-chapter review (page 57-61)

      • Reviewing concepts: 2, 5, 6, 7

      • Applying concepts: 3, 5, 7, 9

      • Problems: 2, 3, 5, 10, 21, 25

Review Answers:

Reviewing Concepts:

2. Skip

5. The slope of the position vs. time graph is velocity

6. a) yes - spin around at a constant speed - since direction is changing, velocity is changing

b) no, speed is part of velocity, so if velocity is constant, speed is constant

7. Both are straight lines beginning at 0, but the runner's line is steeper

Applying Concepts:

3. The space shuttle has traveled a greater distance, but displacement only depends on the start and end points, so displacement is the same for each group.

5. displacement is also zero

7. increasing, constant, decreasing, zero, increasing negative, constant negative, decreasing negative

9. a) when the positions are the same, so 1.4 sec or 8.2 sec

b) Car A has the greater slope, and so the greater velocity

c) at 4 sec, when the slopes are the same (the lines are parallel)

d) the entire time, slope continually decreases for car B

Problems:

2. -85 miles

3. a) zero displacement

b) 6.0 m

5. 1.8 minutes

10. 11 m

21. a) 2.3 m/sec

b) 0.67 m/sec

c) 1.25 m/sec

25. a) graph, sorry, but I can't show that here

b) 6.0 m

c) 24 m

d) 102 m