91Ó°ÊÓ

The mass of the climber is, m = 90 kg

The energy that the climber gets per bar, E = 1.25 MJ $\left(\frac{{10}^6\mathrm{MJ}}{1\mathrm{MJ}}\right)=1.25×{10}^6\mathrm{J}$

The height of the summit of Mount Everest, h = 8850 m

The acceleration due to gravity is,$\mathrm{g}=9.8\mathrm{m}/{\mathrm{s}}^2$

The energy of the climber against the gravitational force from the sea level shows the results that there is a change in potential energy.

Formula:

Change in potential energy, $∆\mathrm{PE}=\mathrm{mg}\left({\mathrm{h}}_2-{\mathrm{h}}_1\right)$ (1)

The work or energy expanded by the climber to go against the gravitational force to climb to the summit of the mountain is given using equation (1):

W = Change in potential energy

$$\begin{gathered} =90\mathrm{kg}×9.8\mathrm{m}/{\mathrm{s}}^2×\left(8850\mathrm{m}-0\mathrm{m}\right) \\ =7.8×{10}^6\mathrm{kg}.{\mathrm{m}}^2/{\mathrm{s}}^2\left(\frac{1\mathrm{J}}{1\mathrm{kg}.{\mathrm{m}}^2/{\mathrm{s}}^2}\right) \\ =7.8×{10}^6\mathrm{J} \end{gathered}$$

Hence, the value of the energy is$7.8×{10}^6\mathrm{J}$ .

The number of candy bars that are required by the climber to supply energy is given as:

$$\begin{gathered} \mathrm{n}=\frac{7.8×{10}^6\mathrm{J}}{1.25×{10}^6\mathrm{J}/\mathrm{bar}} \\ =6.2\mathrm{bar} \\ ≈6\mathrm{bar} \end{gathered}$$

Hence, the required candies are 6 bar .