Skip to Content Go to sign in Skip to Primary Navigation Skip to Page Navigation Skip to Header Navigation Skip to Footer Navigation Toggle Accessibility Options or learn more about accessability

Physics Classroom is making strides to make our site accessible to everyone, and features many accessibility features.

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.

Within the main content, we leverage headers to provide in page or in tool navigation.

Although we are still rebuilding our content to leverage these tools, our images should have both short and verbose descriptions, the later describing in great detail the image for those who cannot see. Any formulas found within the images are often in the image figure below the image.

Equations and formulas are rendered using MathJax, which has both verbal, braille (including nemath braille), and keyboard navigation within them. Learn how to configure and leverage this for various screen readers on our Equation Navigation Page.

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 .

Return to screen reader navigation

Gravity-Free Environment

Suppose a zookeeper must shoot a banana from a banana cannon to a monkey who hangs from the limb of a tree. This particular monkey has a habit of dropping from the tree the moment that the banana leaves the muzzle of the cannon. The zookeeper is faced with the dilemma of where to aim the banana cannon in order to hit the monkey. If the monkey lets go of the tree the moment that the banana is fired, then where should she aim the banana cannon? To ponder this question, first consider a scenario in which there is no gravity acting on either the banana or the monkey. What would be the path of the banana? Would the banana hit the monkey?

Anim'n of Monkey and Zookeeper Demonstration

As is obvious from the animation above, the banana moves in a straight line path in the absence of gravity. As such, a banana aimed directly at the monkey will hit the monkey. In the absence of gravity, the banana moves in a straight line path (and does not experience any downward acceleration) and the monkey does not fall once he lets go of the tree. But what if there were gravity? Where should the zookeeper aim her banana cannon to successfully hit the monkey? Suppose that the zookeeper aims above the monkey's head. Would this lead to success?

To further study the Monkey and Zookeeper dilemma and see additional animations, click on one of the following links.

The Monkey and The Zookeeper

Throw above the Monkey with Gravity On

Throw at the Monkey at a Fast Speed with Gravity On

Throw at the Monkey at a Slow Speed with Gravity On
 

Click on any of the above links to explore the zookeeper's dilemma.

For more information on physical descriptions of motion, visit The Physics Classroom. Detailed information is available there on the following topics:

Acceleration of Gravity

Acceleration of Gravity and the Independence of Mass

Projectiles

Characteristics of a Projectile's Trajectory
 
Tired of Ads? Go Ad Free ($5/year))