Exam1 Study Guide Based on Course Outcomes:

  1. Work with Units: (chapter 1)
  1. Convert units using conversion factors.
  2. Check solutions and equations using Unit Analysis.
  3. Select an appropriate Value and Range for a measured quantity and back up your selection with appropriate reasoning. Report using the format Value +/- Range.
  1. Observe, Analyze and Report the Motion of an Object: (chapter 1-2)
  1. Operationally define position, displacement, time instant, time interval (elapsed time), average velocity, and average acceleration.
  2. Describe what effect a coordinate system change will have on kinematic quantities.
  3. Explain the difference between initial/final velocity, average velocity, change in velocity and instantaneous velocity.
  4. Use motion (kinematic) quantities and equations, motion diagrams, and motion graphs to solve motion problems.
  5. Draw motion graphs from lab data or other representations of motion and interpret the meaning of coordinates, intercepts, slope and area.
  1. Work with Vectors: (chapter 1, 3)
  1. Convert between the component description of a vector and the magnitude and direction description of that vector.
  2. Add and subtract any two vectors using the graphical (drawing) method.
  1. Understand that position, displacement, velocity and acceleration are vectors. Know how to manipulate them to find related vector quantities.
  1. Analyze 2-D Motion: (chapter 3)
  1. Use the kinematic (motion) equations in component form to solve problems.

The exam covers:

Chapter 1 all except significant figures

Chapter 2 all

Chapter 3: Sections 1-4, 6-7

Labs 1-3

Policies:

You may Bring and Use: Calculator, ruler, drawing materials

You must turn off cell phones and place them away from you during the exam

There will be NO BATHROOM breaks. When you leave the room, the exam is finished.

You will be asked to explain your answers so be ready

The exam is a 1 hour exam, you have 1 hour 20 min. to complete it. You may leave when done.

You will be asked to spread out so you may not be seated in your usual location.

I will take off for missing units, no unit analysis (no units in your work), no explanation or work when asked for in the question.

If you are nervous, relax, breath slow and remember that I’m want to know what you know, tell me.

Are You Ready?

Here are some questions that are good practice for checking your understanding. They are here only as sample questions for practice. They are not the same questions that you will see on the exam.

Position (cm) / Time
(min)
0.56 / 2 min
0.55 / 2 min
0.51 / 2 min
0.55 / 2 min
0.54 / 2 min
  • Have you been doing unit analysis checks on your homework?
  • Here is lab data, what should be reported? Or what should you do?

Using the coordinate system below: + or – or 0 for xi, xf, x, vi, vf, v, a?

  • What changes if you reverse the coordinate line?
  • What changes if you move x=0 to the right?
  • What changes if you say t=0 is on the left box?
  • Can you describe a situation where the object speeds up, v is positive and v is negative? Is there more than one situation?
  • If the final velocity is 10 m/s and the average is 8 m/s what is the initial velocity? What is v?
  • If the final velocity is -10 m/s and the average is 0 m/s what is the initial velocity? What is v?
  • Can you plot x vs t, y vs t, vxvs t, vyvs t, axvs t, and ayvs t for any object undergoing projectile motion?
  • Graph Interpretation Problem: (Use the Graph Below)

Below is a position vs. time graph for two objects, A and B. Use the graph to answer the following questions. Show, on the graph, how you find the information.

  1. Which object has the larger speed at t = 3 sec? Find the speed. Find the velocity.
  1. Which object has the larger speed at t = 8 sec? Find the speed. Find the velocity.
  1. Are the objects ever side-by-side (next to each other)? If so, when?
  1. Do the objects ever have the same velocity? If so, when? Same speed?
  1. When are the objects closest together? How close are they?
  1. What is car B doing between 5 and 6 seconds?

  1. Describe the motion in words for each car.
  1. Sketch the v vs. t graph for each car.

Solution guidelines for practice questions above:

For the data question there are lots of possible answers. You might consider whether there is enough data there taking into account the uncertainty or lack of.Should more be taken? Is the uncertainty reasonable and what is it?

For the coordinate systems, compare your answers to the sailboat examples in the lecture.

Looks like the question is a bit covered up.So I will answer for a positive delta v and a negative v. In that case the velocity would be negative and getting closer to zero. For example v1=-3 m/s and v2=-1 m/s is a +2 m/s delta v.

For final v of 10 m/s and average of 8 m/s the initial must be 6 m/s and the delta is therefore 4 m/s.

For final v of 10 m/s and average of 0 m/s the initial must be +10 m/s and the delta is therefore 20 m/s.Did you notice that in this case it turned around?

Answers to CAR A and B Questions

1.Velocity’s are from slopes of tangent lines and are approximate. A’s is -2.5 m/s and B’s is +3.5 m/s so B is faster.

2.Velocity for A is -1 m/s and B’s is -9 m/s and the faster speed is B’s

3.They are never side by side meaning they never are at the same place at the same time.

4.They have the same velocity a bit before 6 sec.

5.They are closest together at a bit just before 6 sec.

6.Car B is turning around between 5 and 6 sec.

7.Car A is slowing down gradually in a direction toward x=0 location. Car B is going the opposite direction with a faster speed and then slows and turns around, then speeds up to a fast constant at the end.

8.Car A’s graph is in the negative area and showing velocities that are negative and getting closer to zero. Car B’s graph starts in positive velocity area and goes down and crosses to negative velocity and after a short time levels off to a constant v.