Skip to Content Skip to Header Navigation
Getting your Trinity Audio player ready...

Hold down the T key for 3 seconds to activate the audio accessibility mode, at which point you can click the K key to pause and resume audio. Useful for the Check Your Understanding and See Answers.

Words and Charts - helpImmortalSage

The kinetic energy (KE) of an object depends upon the speed. The KE value is greatest when the speed is greatest. The gravitational potential energy (PE) is dependent upon the height of the object. The PE is greatest when the height is greatest.

Energy bar charts represent the amount of the various forms of energy by a bar. The height of the bar is indicative of the relative amount of that form of energy. Bar charts typically display the amount of each form of energy in the initial state and the final state of the object.

Each Difficulty Level of this Concept Builder consists of a Matching Pair activities. Students are presented with four motion descriptions and four energy bar charts. They must match the verbal description to the corresponding bar chart. The verbal description and the bar chart shows up on a 3x3 grid with one grid being reserved for instructions and feedback.
 

Immortal Sage Level:

Skydiver falls at a constant speed.
A moving car accelerates across level ground.
Starting from rest, a car accelerates up a hill.
A hot air balloon rises upward at constant speed.

 


Constructing Energy Bar Charts

The construction of an energy bar chart demands that you ...

  1. Identify what forms of energy (kinetic or potential) are present in the initial state.
  2. Identify what forms of energy (kinetic or potential) are present in the final state.
  3. Identify whether the amounts of these forms have increased, decreased or remained constant.
 

About Kinetic Energy and Potential Energy

To determine the above information, you need to know:
  • Kinetic energy (KE) is the energy of motion. If an object is moving then it has kinetic energy. The faster that it moves, the more kinetic energy it will have.
  • Gravitational potential energy (PE) is the energy stored in an object due to its vertical height. If an object is located above the ground height, then it has potential energy. The higher it is located, the more potential energy that it has.

 

Careful Reading: Paying Attention to Clues

As you read each verbal description, learn to pay attention to important words and phrases that help you determine information about the two forms of energy.

Phrases like at constant speed indicates that the KE is not change - it is the same in the initial and the final state. And phrases like accelerates indicates that the KE is changing between the initial and the final state.

A phrase like starting from rest indicates that the KE is initially zero.

Phrases like falls or rises provides information about how the PE is changing. A falling object loses PE and a rising object gains PE.

Try these links to The Physics Classroom Tutorial for help on conducting a bar chart analysis:

Kinetic Energy

Gravitational Potential Energy

Energy Bar Charts