Question

A 75.0kg person is put on an exercise program by a physical therapist, the goal being to burn up 520 food calories in each daily session. Recall that human muscles are about 22.0% in converting the energy they use up into mechanical energy. The exercise program consists of a set of consecutive high jumps, each one 45.0cm into the air (which is pretty good for a human) and lasting 1.50s , on the average.
How many jumps should the person do per session?
How much time should be set aside for each session?

Answer 1

Answer:

1446

36 minutes and 9 seconds

Explanation:

m = Mass of person

h = Height of jump

g = Acceleration due to gravity = 9.81 m/s²

Converting kcal to J

$520\times 4184=2175680\ J$

Efficiency is 22%

$0.22\times 2175680=478649.6\ J$

The potential energy in the jump

$E=mgh\\\Rightarrow E=75\times 9.81\times 0.45\\\Rightarrow E=331.0875\ J$

$\frac{478649.6}{331.0875}=1445.68\ Jumps$

The number of Jumps required is 1446

Time required

$1446\times 1.5=2169\ s$

Time to be set aside for each session is 2169 seconds or 36 minutes and 9 seconds