Question

how much work does a supermarket checkout attendant do on a can of soup he pushes 0.900 m horizontally with a force of 5.20 n? express your answer in joules and kilocalories.

Explanation:

Step1: Recall work - formula

The work - done formula is $W = Fd\cos\theta$, where $F$ is the force, $d$ is the displacement, and $\theta$ is the angle between the force and the displacement. Since the force is applied horizontally and the displacement is also horizontal, $\theta = 0^{\circ}$ and $\cos\theta=\cos0^{\circ}=1$.

Step2: Calculate work in joules

Given $F = 5.20\ N$ and $d = 0.900\ m$, we substitute these values into the work - done formula: $W = Fd=(5.20\ N)\times(0.900\ m)=4.68\ J$.

Step3: Convert work from joules to kilocalories

We know that $1\ kcal = 4184\ J$. So, to convert the work from joules to kilocalories, we use the conversion factor: $W_{kcal}=\frac{W}{4184\ J/kcal}=\frac{4.68\ J}{4184\ J/kcal}\approx1.12\times10^{-3}\ kcal$.

Answer:

$4.68$
$1.12\times 10^{-3}$