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This is referred to as potential energy -work done against gravity. Potential energy is mgh where m is the mass (in our case 4000kg), g is gravity (10ms-2) and h is the height (42.4m). Energy is given in Joules or calories. Energy = 4000 x 10 x 42.4= 1,696,000J One calorie is the same amount of energy as 4.2 Joules. In calories 1,696,000/4.2 = 403,810 calories. In the film there are 3 people to crank the truck, they take it in turns, so each chap will expend 403810/3 = 134 kilocalories. A man’s daily use of energy is 3,000 kilocalories (Three million calories), which suggests that they would be able to do it. We haven’t allowed for the amount of friction from the sand, and the internal friction within the mechanics of the truck, which would be large. Also can the crew provide the torque to move the ambulance? Since turn of the crank effectively starts from a stationary point, moving the truck would be very very difficult. So in fact the amount of energy required would be greater. The desert sun is very very hot and the crew need to look out for dehydration, sunstroke and heat exhaustion. These are the main killers in the desert (except of course for the Nazi troops and the minefield).
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