Answer
The sprinter's average power output is 1170 watts.
The greyhound's average power output is 2000 watts.
Work Step by Step
The work done by the sprinter is equal to the kinetic energy at 3.0 s. We can find the work $W_s$ done by the sprinter.
$W_s = KE$
$W_s = \frac{1}{2}mv^2$
$W_s = \frac{1}{2}(70~kg)(10~m/s)^2$
$W_s = 3500~J$
We can find the sprinter's average power output;
$P_{ave} = \frac{W_s}{t}$
$P_{ave} = \frac{3500~J}{3.0~s}$
$P_{ave} = 1170~watts$
The sprinter's average power output is 1170 watts.
The work done by the greyhound is equal to the kinetic energy at 3.0 s. We can find the work $W_{gh}$ done by the greyhound.
$W_{gh} = KE$
$W_{gh} = \frac{1}{2}mv^2$
$W_{gh} = \frac{1}{2}(30~kg)(20~m/s)^2$
$W_{gh} = 6000~J$
We can find the greyhound's average power output.
$P_{ave} = \frac{W_{gh}}{t}$
$P_{ave} = \frac{6000~J}{3.0~s}$
$P_{ave} = 2000~watts$
The greyhound's average power output is 2000 watts.
