Explanation:
It is given that,
Average power per unit mass generated by Lance, 

(a) Distance to cover race, 
Average speed of the person, v = 11 m/s
If t is the time taken to cover the race.


t = 14545.46 s
Let W is the work done. The relation between the work done and the power is given by :



W = 7090911.75 J
(b) Since, 
So, in 7090911.75 J, 
W = 1694.01 J
Hence, this is the required solution.
To solve this problem, we will get f and then we will use it to calculate the power.
So, for this farsighted person,
do = 25 cm and di = -80
Therefore:
1/f = (1/25) + (1/-80) = 0.00275 = 0.275 m
Power = 1/f = 1/0.275 = +3.6363 Diopeters.
This means that the lens is converging.
The answer is Earths rotation
These actions are an example of feedback.
Given that the room has reached the desired temperature, there is no more need for it to be heated, at least until the temperature drops a bit. This is why the thermostat sends feedback about this situation to the heater, which immediately switches off until it is needed again.