Friday, November 29, 2013

Energy while swimming

Thinking about objects having translational and rotational kinetic energy I wanted to take a look at the energy I have while swimming. A few assumptions had to be made as well as simplifying the movement but it gives an approximation. I assumed my arms move in circles, my arms are uniform rods, and my leg and other movement is ignored.

Givens: 25.61s to cover 50m, about 17 strokes for each arm, .75m arm, 12kg arm, 87kg total

Total KE=.5mv^2+.5Iw^2+.5Iw^2

v=50m/25.61s=1.95m/s
w=17rev/25.61s*2pi radians/1 rev=4.17 radians/s
I=1/3mL^2=1/3(12kg).75m^2=3.38 kgm^2

.5(87kg)(1.95m/s)^2+2(.5(3.38kgm^2)(4.17rad/s)^2)=224J



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