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Physics Classroom is making strides to make our site accessible to everyone. Our site contains 6 navigation areas. The Primary, Secondary, and Page Level navigations have a screen reader version of their nav structure that allows using the left and right keys to navigate sibling navigation items, and up or down keys to navigate parent or child navigation items. The others can be navigated using tabs. The Primary Navigation handles the first 2 levels of site pages. The Secondary (which is not always available) handles the 3rd and 4th level of structure. The Page level navigation allows you to navigate the current page's headings quickly. The Header Navigation contains the Light/Dark Mode toggle, Search, Notifications and account login. The Breadcrumb Navigation contains the breadcrumb of the current page. If the current page has a breadcrumb, you can get to it by skipping to the content and tabbing in reverse (shift plus tab). The Footer Navigation contains links such as Privacy, Contact, about and terms. Some resources contain an Audio Player that can be activated by holding down the T key for 3 seconds, and then using K to pause and resume. While not every area of Physics Classroom is usable purely from keyboard and screen reader, we are committed to continue work on making this possible. If you have questions or need additional help, please use this link to contact us.

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Free Fall - Directions

Using the Free Fall Concept Builder is quite simple. You will be presented with a position-time graph and a question. There are three different activities, each with a different emphasis. In each activity you will be presented with a question that you will have to answer. In the first activity - Describing Free Fall - you will be presented with a collection of multiple choice questions that focus on the nature of the velocity and acceleration (direction, changes or constancy). Most questions have two parts and two corresponding answers. You will tap on one of the answer choices and it will be hilighted (red text and a red-colored selection button). You can deselect your choice (by tapping on it a second time) or select a different choice (by tapping on it). Once you have selected answers to both questions, a Check Answer button appears. Once you are satisfied with your answers, tap on the Check Answer button. Your answers will be evaluated and your Progress Report will be updated.

In the second activity - Speedometer - you will be presented with a trajectory diagram for a 30 m/s, 40 m/s, or 50 m/s upward launch. Locations of the object at 1-second intervals of time are shown on the diagram and labeled with a letter. You must determine the location on the diagram where the object has a specified speed and direction. You select your answer by tapping on the answer field. Tapping toggles the displayed answer through the list of possible answers. Select your ffavorite answer and tap on the Check Answer button. Your answer will be evaluated and your Progress Report will be updated.

In the third activity - It's About Time - you will be presented with information about the speed and direction of a free-falling object at a given time. You will have to use the acceleration caused by gravity to determine the approximate time at which the projectile will have two other specified speeds and directions. You can select your answer by tapping on the Answer field. Doing so toggles through all the possible choices. For a few of the questions, there is an option "Not possible" that will appear after tappging through all the numbers. Once you have selected times to both speeds, a Check Answer button appears. Once you are satisfied with your answers, tap on the Check Answer button. Your answers will be evaluated and your Progress Report will be updated.

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