Aweightlifter curls a 30 kg bar, raising it each time a distance of 0.50 m .how many times must he repeat this exercise to burn off the energy in one slice of pizza? assume 25% efficiency. energy content of one slice of pizza is 1260 kj.

Explanation:

Each time the work done to raise a given mass is

here we know that

now we have

since it is just 25% of actual energy consumed as we know its efficiency is 25%

so we have total energy consumed in this way

now if it took N number of times so burn the fat of a pizza then

we need to know the time interval during which the force acts. impulse of force = momentum change

this could be newton#'s law of cooling. the cooling curve is exponential