Work done when lifting a barbell

Definition

Work done on an object is defined as the product of the force applied to the object and the distance over which the force is applied in the direction of the force.

\begin{array}{r} W = F \cdot d \end{array}

where $W$ is the work done in joules $(J)$ , $F$ is the force applied in newtons $(N)$ , and $d$ is the distance in meters $(m)$ .

Work Done in Lifting a Barbell

How much amount of work is done in lifting a 200 kg barbell?
To calculate the work done in lifting the barbell, the first thing to consider is the force required to overcome the gravitational force acting on the barbel. This can be calculated by the formula $F = m a$ . The acceleration due to gravity is approximately $9.8 m / s^{2}$ on the earth. So, with the mass of the barbel $m = 200 kg$ , we obtain

\begin{array}{r} F = 200 \cdot 9.8 = 1960 N . \end{array}

Assuming the barbell is lifted vertically from the chest to a fully extended arm position, covering a distance of $d = 50 cm = 0.5 m$ , the work done is

W = 1960 \cdot 0.5 = 980 J

The work done in lifting $200 kg$ barbell is only $980 J$ . This amount is approximately equivalent to the energy contained in 3 grains of cooked rice.