This Concept Builder is intended for use in the middle to later stages of a learning cycle on Newton's second law of motion. Most physics course spend considerable time using physics formulas to solve numerical word problems. Algebraic manipulation and substitution of known values into the formula is a typical activity. This is one way Newton's second law is used in order to better understand the value of the equation. This Concept Builder provides students with plenty of practice solving F_net = m•a problems. 

There are three difficulty levels in this Concept Builder. The difficulty levels are distinguished from one another by the complexity of the problems included at each level. For the Apprentice Difficulty Level, there is an object moving to the right and accelerating to the left under the influence of friction. There is no rightward force upon the object. There are two questions in this Difficulty Level. Each question provides a problem statement, a free-body diagram with blanks for the three forces and three blanks for mass, acceleration, and net force. Students tap on a blank to pop up a numerical keyboard that allows them to enter the answers. Students can check one answer blank at a time or all at once. Students must complete the first question before they can procede to the second question. The two questions differ from one another in terms of what information that is given and what the unknown values are. 

The Master Difficulty Level involves an object moving to the right and accelerating to the right. There are four forces on the object. There is a rightward or forward force; we just refer to it as an applied force with symbol F_app since there is no further detail regarding the source of the force. There is also a leftward friction force. There are three questions in this difficulty level. The three questions differ from one another in terms of what information that is given and what the unknown values are. Students must complete all blanks for the first question before they are presented the second question.

The Wizard Difficulty Level involves an object moving to the right and accelerating to the right. It is much like the Master DIficulty Level with the additional complexity of there being a coefficient of friction. There are four forces on the object - which includes a rightward applied force and a leftward friction force. There are three questions in this difficulty level. The three questions differ from one another in terms of what information that is given and what the unknown values are. Students must complete all blanks for the first question before they are presented the second question.

All questions include randomly generated numbers. So two students sitting side by side will never see an identical problem. The number of misses is kept track of and used to determining a Health Rating. Information about the health bar and percent value are provided on a separate page. The best health rating is always displayed on the Main Menu screen once a difficulty level is completed. Since students can attempt each question an infinite number of times, it is important that there be a health rating to discourage guessing. Teachers who use the activity in class can require that students complete a difficulty level with a minimum specified health rating.  Students can always redo a difficulty level in an effort to improve the health rating. The highest rating is always displayed on the Main Menu screen. 

The most valuable (and most overlooked) aspect of this Concept Builder is the Help Me! feature. Each question group is accompanied by a Help page that discusses the specifics of the question. This Help feature transforms the activity from a question-answering activity into a concept-building activity. The student who takes the time to use the Help pages can be transformed from a guesser to a learner and from an unsure student to a confident student. The "meat and potatoes" of the Help pages are in the sections titled "How to Think About This Situation:" Students need to be encouraged by teachers to use the Help Me! button and to read this section of the page. A student that takes time to reflect upon how they are answering the question and how an expert would think about the situation can transform their naivete into expertise. 

NOTE:  If you are using Concept Builders with a Task Tracker account, the Health Rating is not saved by the system. It is computed on each session but when progress is retrieved from Task Tracker it will report a Health Rating of "--%".

 

 

There are numerous resources at The Physics Classroom website that serve as very complementary supports for the Solve It! (with Newton's Second Law) Concept Builder. These include:

Additional resources and ideas for incorporating Solve It! (with Newton's Second Law) into an instructional unit on Newton's Laws can be found at the Teacher Toolkits section of The Physics Classroom website.  Visit Teacher Toolkits.