# A 60kg softball player, who is 1.75 m tall, performs 12 repetitions of a 140 kg squat. If there...

## Question:

A 60kg softball player, who is 1.75 m tall, performs 12 repetitions of a 140 kg squat. If there is a 1 m chance from the starting position to the bottom position, how much work is accomplished during the entire set? How much potential energy is stored at the starting position?

## Energy and work:

Energy is defined as the capacity of an object of doing work. Energy can be transferred from object to object, which will manifest as work or in the form of heat, increasing the temperature of an object. On the other hand, work is the process of energy transfer associated with the displacement of an object due to force working on it. Work can be calculated through the multiplication of the force and the distance displaced by the object. We have to consider that only the forces working in the same direction of the displacement are taken into account when calculating the work value.

{eq}W=F\times d {/eq}

The amount of work will consist of the change of energy that occurs when the softball player lefts up 1 meter. The player will not only lift its own weight but also the weight used to do the squats. We calculate the amount of energy needed to do one squat first.

{eq}W=(m_p+m_s)gh\\ W=(60+140)(9.8)(1)\\ W=1960\ J {/eq}

This value must be multiplied 12 times, which represents the 12 repetitions.

{eq}W_t= 12\times W\\ W_t=23520\ J {/eq}

At the starting position, the player is 0.75 meters above the ground. We can proceed and calculate the potential energy stored within the system

{eq}E_p=mgh\\ E_p=(60)(9.8)(0.75)\\ E_p=441\ J {/eq}