Real-Life Math -- Solution
1. How far does your client travel each second using his current prosthesis?
22 inches per step x 2.2 steps per second = 48.4
He walks 48.4 inches per second.
2. How fast does your client walk, in miles per hour, using the old prosthesis?
Mph = (48.4 inches per second x 60 seconds per minute x 60 minutes per hour) / 63,360 inches per mile
Mph = (2,904 x 60) / 63,360
Mph = 174,240 / 63,360
Mph = 2.8
At this rate, he walks 2.8 miles an hour.
3. How far does your client travel each second using the new prosthesis?
24.4 inches per step x 2.5 steps per second = 61
He walks 61 inches per second.
4. How fast does your client walk, in miles per hour, using the new prosthesis?
Kph = (61 inches per second x 60 seconds per minute x 60 minutes per hour) / 63,360 inches per mile
Kph = (3,660 x 60) / 63,360
Kph = 219,600 / 63,360
Kph = 3.5
With the new prosthesis, he walks 3.5 miles an hour.
5. How much farther can he walk each hour with the new prosthesis?
3.5 - 2.8 = 0.7
At this rate, the new prosthesis will let your client walk 0.7 miles farther each hour. He'd have to be quite an athlete to keep up that pace!
Prosthetics designers need good math skills, especially to get through university. Also, some prosthetics designers do research, which involves a lot of math.
"We get a lot of that training in school -- college-level physics and basic math skills," says certified prosthetist Kerry Calder. "Research is where most of the math skills would come in."
Researchers use math for things such as biomechanical analysis, figuring out the speed of a person's gait pattern, or measuring how much pressure is being put through a foot.
Prosthetics designers need to do a lot of measuring, in both metric and imperial. They also use factors such as the client's weight and activity level to design and fit the prosthesis to the client.
"It's all laid out in charts for you, so there's not really too much math involved there," Calder says. "Basically, after that, it's all measurement."
So, if you want to be a prosthetics designer, get a tape measure. And for good measure, make it a nice one!