a)Compare the work done by the boy in running and walking upstairs.Why?b)Compare the power the boy expended in running and in walking.Why?c)Which will be tiresome running or walking upstairs?Why?
2007-09-06 23:05:12 · 3 answers · asked by Anonymous in Science & Mathematics ➔ Physics
work is force x distance...
power is rate of work or work / time.
a. since force = mass*acceleration...
running has a larger acceleration than walking...
thus running needs a larger force than walking
since work = force x distance
thus, running has a larger work expenditure than walking.
b. by running the time to reach the top of the stairs is smaller than by walking...
since the running has larger work than walking..
and
since power = work / time
thus running expends more power than running..
c. obviously running upstairs...
why? you will be spending a larger amount of work and power..
2007-09-07 01:19:52 · answer #1 · answered by quigonjan 3 · 0⤊ 0⤋
A) Work is force x distance but it is also the energy expended to move an object over that distance. Since the energy needed to climb a stair of height h is approximately equal to mgh no matter how fast you do it running and walking does the about the same amount of work.
B) power is energy per unit time so more power is needed for running than for walking.
C) Our body produces energy at a constant rate, and when we expend energy faster than we produce it, we get "tired", so running will make you more tired.
2007-09-07 01:49:16 · answer #2 · answered by meg 7 · 0⤊ 0⤋
Work and power are the same.
More tiresome to run because the same amount of energy is expended over a shorter time.
2007-09-06 23:13:27 · answer #3 · answered by Rob B 7 · 1⤊ 1⤋