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Question
An adult weighing 600 N raises the centre of gravity of his body by 0.25 m while taking each step of 1 m length in jogging. If he jogs for 6 km, calculate the energy utilised by him in jogging assuming that there is no energy loss due to friction of ground and air. Assuming that the body of the adult is capable of converting 10% of energy intake in the form of food, calculate the energy equivalents of food that would be required to compensate energy utilised for jogging.
Solution
Given, weight of the adult (w) = mg = 600 N
Height of each step = h = 0.25 m
Length of each step = 1 m
Total distance travelled = 6 km = 6000 m
∴ Total number of steps =
Total energy utilised in jogging = n × mgh
= 6000 × 600 × 0.25 J
= 9 × 105 J
Since 10% of intake energy is utilised in jogging.
∴ Total intake energy = 10 × 9 × 105 J = 9 × 106 J.
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