## Newton's Laws of Motion

Force
When forces are unbalanced, objects accelerate. But what factors affect the amount of acceleration? This Interactive allows learners to investigate a variety of factors that affect the acceleration of a box pushed across a surface, The amount of applied force, the mass, and the friction can be altered. A plot of velocity as a function of time can be used to determine the acceleration.

Now available with a Concept Checker.

Free-Body Diagrams
The Free-Body Diagrams Interactive is a skill-building tool that presents users with 12 physical situations for which they must construct free-body diagrams. On-screen buttons are used to select up-down-right-left force types. Force arrows can be clicked/tapped to toggle the magnitude of the force. Feedback is immediate; opportunities to correct answers are endless. Built-in score-keeping makes this Interactive a perfect candidate for a classroom activity.

Free-Body Diagrams ... The Sequel
If you enjoyed the Free-Body Diagrams Interactive and you need more practice, then you need to try Free Body Diagrams ... The Sequel. Like the original version, it provides 12 physical situations for which you must construct free-body diagrams. These are different than the 12 scenarios of the original Free-Body Diagrams Interactive. Yet it operates in the same manner - pick a direction, identify the force type in that direction, and size it appropriately relative to the oppositely-directed force.

Rocket Sledder
Created by our friends at Nerd Island Studios, this Interactive illustrates the effect of friction, air resistance, and applied force upon a sledder. The speed, acceleration, and force values are displayed as the sled moves. Learners can vary the mass of the sledder and the size of the parachute that is attached to it.

Now available with a Concept Checker.

Falling Bodies - 1D
The Falling Bodies 1D interactive is a numerical modeling program that models the falling motion of an object in the presence of air resistance. Learners set the properties of the falling object (mass, initial height, initial velocity, profile area, drag coefficient, air density, etc.), then tap a button and bbzzammm ... the program calculates information about height, velocity, acceleration (and more) at regular, pre-set intervals of time. The resulting calculated data is displayed in the form of a spreadsheet. A graphical display of the data can be viewed with the mere tap of a button. Best of all, learners can ask a What if ...?-styled question and explore the answer. What if the skydiver had a greater mass? What if there was no air resistance? What if the fall occurred on the moon instead of on Earth? What if I just tap the link and get started on my own exploration? Yes! Good idea - tap the link and get started.

Skydiving
Created by our friends at Nerd Island Studios, this Interactive allows the learner to explore the motion of an object falling under the influence of air resistance. Force arrows and values are shown as the object falls. A speedometer displays the speed of the object; the height is listed as well. The mass of the falling object and the size of its parachute can be varied. Enjoy the Skydiving Interactive without the fear of falling.

Now available with a Concept Checker.

You might have wondered why you get that queasy feeling in an elevator as you start up and slow down. The phenomenon is explained by some simple physics. This Interactive allows a learner to explore the physics behind the sensations of weightlessness and weightiness ... and you won't get sick in the process.

Now available with a Concept Checker.
Everyone is fascinated by pulleys. In this Interactive, learners will attach two objects together by a string and stretch the string over a pulley. Both an Atwood's machine and a modified Atwood's machine can be created and studies. Change the amount of mass on either object, introduce friction forces, and measure distance and time in order to calculate the acceleration.

Balanced vs. Unbalanced Forces
The Balanced vs. Unbalanced Force Interactive is a skill-building exercise that challenges students to associate representations of an object's motion with the presence of balanced or unbalanced forces. Several representations are used including dot diagrams, position-time graphs, velocity-time graphs, position-time tables, and velocity-time tables. The Interactive offers three different levels of difficulty and includes built-in progress-tracking for each level. Every question is accompanied by a Help page that includes question-specific help relevant to the question.The Interactive makes a great classroom activity for the transition from Newton's first law to Newton's second law.

NOTE: The Balanced vs. Unbalanced Forces activity has been moved to our Concept Builders section. The links included here will direct you to that section.