Question

A student with a mass of 65.5 kg runs up a flight of 18 stairs. Each of the steps has a height of 16.5 cm. The student was able to reach the top of the stairs in 2.57 s while climbing it 1 stair at a time.
1. Determine the student’s body power

2. If the student changed the number of steps taken in each step (i.e. 2 at a time OR 3 at a time) but nothing else changed, would this change the power of the student? Explain.

3. A Big Mac meal from McDonalds has 4 853 440 J of energy (1160 calories!). Using your answer from number 1, determine how long it would take for you to convert all the energy in a Big Mac meal (if only running stairs at the same rate). Express your answer in minutes.

Answer 1

The power developed by the student is 756.9 J/s and remains the same if the student takes the same time to climb the stairs when climbing it in two's and three's.

What is power?

Power is the rate at work is done.

• Power = work done/time
• work done = mass × acceleration due to gravity × height

Work done = 65.5 × 10 × (18 × 0.165) = 1945.35 J

Power = 1945.35/2.57 = 756.9 J/s

If the student climbed the steps in two or three at a time, the power does not change if the time remains the same.

• Time required = Energy/ power

The time required to convert the Big Mac meal from McDonalds = 4 853 440/756.9

Time required = 6412.26 seconds

Therefore, from the power developed by the student, it will take him 6412.26 seconds to convert all the energy in a Big Mac meal.

Learn more about power at: brainly.com/question/1634438

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