# kinetic energy question on rackets mass and speed

Discussion in 'Racquets' started by rst, Dec 30, 2012.

1. ### rstRookie

Joined:
Jan 23, 2012
Messages:
257
Location:
northern nv
"When I run, I begin to sweat because for every 3 Joules of kinetic energy my muscles put into me moving they create 7 Joules of heat, which I must get rid of or my body chemistry breaks down and I die. ............." from

http://www.sciforums.com/Can-Sound-...with-specific-frequency-of-sound-t-83422.html

i inputted some values for racket weight and velocity on an K calculator

a 10.7 oz racket and 12.7 ounce each at 20mph gave a difference of about 2.2 J(oules?) would this also mean that perstroke the heavier racket would cause nearly 6.5 joules of bodyheat in excess of the lighter racket????

2. ### Steve HuffLegend

Joined:
Feb 11, 2004
Messages:
7,432
Technically, yes. You have to work harder to swing more mass. But, you have to calculate using swing weight, as it takes more energy to swing a stick with a weight on the end than it does one with the weight closer to the hand. If you were just holding a racket, the static weight could be used for determining energy used.