A student eats a dinner rated at 2000 (food) Calories. He wishes to do an equivalent amount of work in the gymnasium by lifting a 50 kg mass. How many times must he raise the mass to expend this amount of energy? Assume that he raises it a distance of 2 m each time and that he regains no energy when it is dropped to the floor. The acceleration due to gravity is 9.8 m/s2 and 1 food Calorie is 103 calories.

Question

Physics

Alexis Hester

5 May, 16:56

A student eats a dinner rated at 2000 (food) Calories. He wishes to do an equivalent amount of work in the gymnasium by lifting a 50 kg mass. How many times must he raise the mass to expend this amount of energy? Assume that he raises it a distance of 2 m each time and that he regains no energy when it is dropped to the floor. The acceleration due to gravity is 9.8 m/s2 and 1 food Calorie is 103 calories.

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Answers (1)

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Keyon Lambert · Answer 1

879.49

Approximately 880 times

Explanation:

2000 (food) Calories = 2000 * 103 calories

2000 (food) Calories = 206000 cal.

Work done by the boy is given by Mgh, potential work

Work = 50*2*9.8

Work = 980 joules.

1 kilocalorie =

4184 joules

So 1 cal = 4.185 joules

206000 calories = 206000*4.184

206000 cal = 861904 joules.

To extend 206000 cal,

He will lift the 50 kg mass 861904/980 times

= 879.49 times.