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Telling Time

A clock is a device, either mechanical or digital, that measures time in hours, minutes, and sometimes seconds. 

 

 

A mechanical clock shown below has a face with number 1 to 12 written around the perimeter and 3 hands to indicate the time of day.

             

The shortest hand (red) points to the hour of the day (for example, 1 o'clock, 2 o'clock, ..., 12 o'clock). When the hour hand makes a full circle around the clock once - 12 hours have passed, and since there are 24 hours a day, the hour hand goes around the clock 2 times a day. 

The longer hand (thick black) hand on the clock is the minute hand, and it indicate the minute of the hour. This time, the numbers on the clock face is counted by 5 (1 means 5, 2 means 10, 3 means 15, ..., 12 means 60). You can also count the minute from the smaller tickmark at the very ouer edge of this clock. 

 

For example: The red hand is between 1 and 2 (but not yet reaches 2), so it's 1 o'clock. The black hand is pointing at number 5, so it's 5, 10, 15, 20, 25 minutes.

It's 25 minutes past 1 o'clock or 1:25.

The second hand (often not shown) is the longest, thinnest, and fastest hand of the clock, and it indicates seconds. Reading the second hand is the same as reading the minute hand. 

Linkbot Image Mindstorm Image Cursor Image
0x126-6-12y126-6-12
Grid:
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Axes: x-axis y-axis Show Grid
Grid: 24x24 inches 36x36 inches 72x72 inches
96x96 inches 192x192 inches
Quad: 4 quadrants 1 quadrant Hardware
Units: US Customary Metric
Background: Background Image

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Robot 4
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Current Position: (0 in, 12 in)
Current Angle: 0 deg
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Learning the Clock (Hour Hand)
Problem Statement:

Run the code and input value to watch the hour hand of a clock in action

/* Code generated by RoboBlockly v2.0 */
#include <chplot.h>
double hour;
CPlot plot;

// Describe this function...
void Winding_the_Clock() {
  double i;
  double i_inc = 0.05;
  if (0 > hour) {
    i_inc = -i_inc;
  }
  i = 0;
  while(i_inc >= 0 ? i <= hour : i >= hour) {
    //plot.backgroundImage("./Background.png");
    plot.strokeColor("black");
    plot.line(0, 0, 0, 7.2);
    plot.strokeColor("red");
    plot.line(0, 0, 6 * cos(deg2rad((90 - i * 30))), 6 * sin(deg2rad((90 - i * 30))));
    delaySeconds(0.01);
    i += i_inc;
  }
  //plot.backgroundImage("./Background.png");
  plot.strokeColor("black");
  plot.line(0, 0, 0, 7.2);
  plot.strokeColor("red");
  plot.line(0, 0, round((6 * cos(deg2rad((90 - hour * 30))))), round((6 * sin(deg2rad((90 - hour * 30))))));
}

// Example: It's 3 o'clock. Input 3 into the prompt
plot.strokeWidth(6);
plot.strokeColor("black");
plot.line(0, 0, 0, 7.2);
plot.strokeColor("red");
plot.line(0, 0, 0, 6);
delaySeconds(0.1);
hour = 3;
Winding_the_Clock();

plot.label(PLOT_AXIS_XY, "");
plot.grid(PLOT_OFF);
plot.tics(PLOT_AXIS_XY, PLOT_OFF);
plot.axis(PLOT_AXIS_XY, PLOT_OFF);
plot.axisRange(PLOT_AXIS_XY, -12, 12);
plot.ticsRange(PLOT_AXIS_XY, 2);
plot.sizeRatio(1);
plot.plotting();
Blocks Save Blocks Load Blocks Show Ch Save Ch Workspace
Problem Statement:

Run the code and input value to watch the hour hand of a clock in action

 

		

			

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