Question

The stair stepper is a novel exercise machine that attempts to reproduce the work done against gravity by walking up stairs. With each step, Brad (of mass 80 kg) simulates stepping up a vertical distance of 0.15 m with this machine. If Brad exercises for 18 min per day with a stair stepper at a frequency of 50 steps per minute, what total work he does he do each day? The acceleration of gravity is 9.8 m/s^2 . Answer in units of J.

Answer 1

Brad does about 105840 Joules (J) of work each day with the stair stepper.

Step-by-step explanation:

To calculate the work done by Brad, we need to find the force he exerts and the distance he moves against gravity with each step, and then multiply by the number of steps per day.

The force Brad exerts is equal to his weight, which is:

F = mg = (80 kg) x (9.8 m/s^2) = 784 N

The distance Brad moves against gravity with each step is 0.15 m.

The total number of steps Brad takes each day is:

steps = (18 min/day) x (50 steps/min) = 900 steps/day

Now we can calculate the work done by Brad each day as follows:

work = force x distance x number of steps

= (784 N) x (0.15 m) x (900 steps)

= 105840 J

Therefore, Brad does about 105840 Joules (J) of work each day with the stair stepper.