The difficulty in acquiring a target such as using your mous

The difficulty in \"acquiring a target\" (such as using your mouse to click on an icon on your computer screen) depends on the distance to the target and the size of the target. According to Fitts\'s Law, the index of difficulty (ID) is given by

ID =

where W is the width of the target and A is the distance to the center of the target. Find the index of difficulty of clicking on an icon that is 3 mm wide and one that is 6 mm wide. In each case, assume that the mouse is 50 mm from the icon. (Round your answers to two decimal places.)

Solution

ID = log(2A/W)

where A ---- is the distance to the center of the target;

W---- is the width of the target

a) W = 3mm ; A = 50 mm

ID = log(2*50/3) = 1.52

b )W =6mm ; A = 50 mm

ID = log(2*50/6) = 1.22