Question

Assuming a typical efficiency for energy use by the body, how many slices of pizza must you eat to walk for 2.5 h at a speed of 5.0 km/h? Assume that your mass is 68 kg, metabolic power of 68 kg individual walking at 5 km/h is 380 W, and the energy content of slice of pizza is 1260 kJ.

Answer 1

2.7 Pizzas.

Step-by-step explanation:

The power required to walk through 5km in 1 hour is 380W.

A watt is basically Jules per second, then we need to standardized this measurement to second.

5km/hr is equal to,

`(5km)/(hr)*(1hr)/(3600s)*(1000m)/(1km)=1.389m/s`

Walking by 2.5 hours is equal to a distance of,

`d=v*t=1.389*(2.5*3600) = 12500m`

The total energy required then would be,

`E = (380J)/(1.389m/s)(12500)=3.4199*10^6J`

Then we know that one pizza slice gives
`1260*10^3J` of energy, the total pizza needed are,

`\eta = (3.4199*10^6)/(1260*10^3) = 2.7142`

Then you need to buy 3 pizza.