ChemPhys 173/273

Unit 6: 1-Dimensional Kinematics

Problem Set A

Overview:

Problem Set A targets your ability to use the average velocity and average acceleration equations. There are a few routine problems and several more complicated multi-step problems. The equations for average velocity (vave) and average acceleration (aave) are stated below.

An inspection of these equations shows that there are clear mathematical relationships between the following sets of quantities:

 From the top equation: average velocity (vave), initial velocity (vi), final velocity (vf), dispacement and time From the bottom equation: average acceleration (aave), initial velocity (vi), final velocity (vf) and time

Of the fifteen problems on the set, a few involve rather routine calculations while several involve more complicated multi-step analysis. Whether routine or difficult, it is always a worthy endeavor to practice the habits of a effective problem-solver. These habits are described below.

Habits of a Effective Problem-Solver:

An effective problem solver by habit approaches a physics problem in a manner that reflects a collection of disciplined habits. While not every effective problem solver employs the same approach, they all have habits which they share in common. These habits are described briefly here. An effective problem-solver ...

• ... reads the problem carefully and develops a mental picture of the physical situation. If needed, they sketch a simple diagram of the physical situation to help visualize it.
• ... Identifies the known and unknown quantities in an organized manner, often times recording them on the diagram iteself. They equate given values to the symbols used to represent the corresponding quantity (e.g., vi = 0 m/s, a = 2.67 m/s/s, vf = ???).
• ... plot a strategy for solving for the unknown quantity; the strategy will typically center around the use of physics equations.
• ... identify the appropriate formula(s) to use, often times writing them down. Where needed, they perform the needed conversion of quantities into the proper unit.
• ... perform substitutions and algebraic manipulations in order to solve for the unknown quantity.

To be successful on this problem set, you will need to be able to:

• give attention to the units of stated quantities and peform proper conversions.
• utilize the average speed and average velocity equations effectively.
• know that a rebounding situation results in a final velocity which has the opposite direction (i.e., mathematical sign) than the initial velocity.
• employ the habits of a good problem-solver.

The following pages from The Physics Classroom tutorial may serve to be useful in assisting you in the understanding of the concepts and mathematics associated with these problems.

Distance and Displacement | Speed and Velocity | Acceleration

View Sample Problem Set.

 Problem Description Audio Link 1 Calculation of average speed from knowledge of distance and time; conversion of units required. 2 Calculation of the time to complete a circular trip if given the average speed and information for determining the circumference. 3 Determination for the time of motion if given the distance and the average speed; conversion of units required. 4 Determination of the total displacement for a two-phase motion if given the average speed and the time for each phase of the motion; conversion of units required. 5 Referring to the previous problem; determination of the average velocity; ; conversion of units required. 6 Complex analysis of a beetle race to determine the separation distance between the winning beetle and the losing beetle; conversion of units required. 7 Calculation of the average velocity of the first phase of a two-stage round-trip motion. 8 Referring to the previous problem; determination of the average velocity of the entire round-trip motion. 9 Complex analysis of a two-stage motion to determine the total time of travel; conversion of units required. 10 Routine calculation of acceleration; conversion of units required. 11 Routine calculation of acceleration from initial and final velocity values and the time. 12 Routine calculation of acceleration from initial and final velocity values and the time. 13 Calculation of acceleration for a rebounding situation. 14 Use of acceleration equation to determine a final velocity. 15 Routine calculation of acceleration from initial and final velocity values and the time; conversion of units required.

Audio Help for Problem: 1 || 2 || 3 || 4 || 5 || 6 || 7 || 8 || 9 || 10 || 11 || 12 || 13 || 14 || 15 ||

Retrieve info about: Problem-Solving || Audio Help || Technical Requirements || CD-ROM