Unit 8 continued

Let's say that there are two kids racing. Rai is about 40 kg, and Janelle is about 45 kg and both complete a short race of about 5 meters in 3 seconds. So we want to find out the power that each individual kid can develop during this race. Power, or the rate at which work is done, is calculated by using the equation, change in energy/ change in time and is measured in watts. So first we must find work done by each kid. To find work we use the equation, force x distance traveled. So force is mass x gravity, and the distance for both of them is 5 meters. Rai gets about 1960 Joules of work done, while Janelle gets about 2205 Joules of work done. So in the end, Rai develops 653.3 watts of power, while Janelle develops about 735 watts of power.

Now let's say Rai decides to race with a lemon suit on, which adds 7 kg to her mass. Now who will develop more power in the end if the other variables are unchanged? So Rai would get about 2303 Joules of work done, and develops 767.7 watts of power. So this shows that the greater the mass, the more power it can develop!