|
Energy Changes Bars
Tool: The Energy Changes Bars
Tool plots colored bars that display the energy put into an
object, the energy put out by th eobject, and the changes in
the object's internal energies. This tool only plots in
Run
mode.
Place
an energy bars tool by first selecting the target body, then
clicking on the Energy Bars button, and finally clicking at
the desired position of the bar graph. You can later
reposition the energy bars tool.
In the energy bars tool's
Properties
Box, you can set:
- Refresh time. How often
the tool redraws the energy bars. The default value is
0.2 sec. The shortest refresh time, 0.1
sec, means the energy bars have the same temporal
resolution as the clock.
However, at such a short refresh time, energy readouts
are difficult to read.
- Show energy readouts.
Controls whether energies are displayed as numbers as
well as bars. Default option is to display the
readouts.
- View mode. Determines
the size of the Energy Changes Bars display. You have
three choices,
min mode,
normal mode, and
max
mode. The figure at the bottom
of this help page illustrates the differences between the
three modes.
- Scale mode. You have
two choices,
auto
mode or
hand
mode. For descriptions of
these two modes and what you need to consider in making
the choice, see Choosing
Scale Mode on the
graph
tool's help page.
- Maximum value.
Hand
mode only: Sets the maximum
energy value displayed by the bars. In
auto
mode, setting this value has
no effect.
- Measure in kJ. Controls
whether energy bars and readouts display energies in
joules (default) or kilojoules.
|
The figure below illustrates the
layout and the three different View modes
of the Energy Changes Bars tool. Three
body
elements of different
masses (Brick [8 kg], Book [2 kg],
Balloon [0.5 kg]), are being dragged
(pulled)
along rough surfaces with forces of 50 N.
|
|
|
For each body, the Energy
Input to the body by the dragging force is
displayed in the top row. The second row displays
the Energy Output to the surface by
the body due to friction. The third row displays
the Energy Changes in System (i.e.,
in the body) as a result of being subjected to
various forces.
|
|
