Answer :
Formula for the work is
W=Fs
where F is force and s is distance
Now we can just substitute our data and find work
W=130N*2m=260J
The result is 260J.
W=Fs
where F is force and s is distance
Now we can just substitute our data and find work
W=130N*2m=260J
The result is 260J.
The absolute minimum work required for that job is the potential energy that will be added to the trunk by moving it up 2meters.
Potential energy = (weight) x (height) = (130 N) x (2) = 260 Joules
That's the absolute minimum, because the trunk itself needs that much
energy in order to get up there. But if you're doing the lifting, you may need
to expend more energy than that, just because the human body is not a
100% efficient machine. It always takes more work to do something physical
than the energy you actually deliver to the job.
Here's a mind-blowing factoid:
Do you see that 260 joules up there in the answer to the trunk ?
If you eat, let's say, 1800 Calories a day and don't gain any weight, that means
that you're burning off 260 joules of energy about every 3 seconds ! ! !
Just to keep your body warm, keep your breathing going, keep your brain
in tune, and move yourself around !
Enough energy to lift that 30-pound trunk about 6-1/2 feet straight up off
the floor !
1 Calorie = 4184 joules
1 day = 86,400 seconds
Potential energy = (weight) x (height) = (130 N) x (2) = 260 Joules
That's the absolute minimum, because the trunk itself needs that much
energy in order to get up there. But if you're doing the lifting, you may need
to expend more energy than that, just because the human body is not a
100% efficient machine. It always takes more work to do something physical
than the energy you actually deliver to the job.
Here's a mind-blowing factoid:
Do you see that 260 joules up there in the answer to the trunk ?
If you eat, let's say, 1800 Calories a day and don't gain any weight, that means
that you're burning off 260 joules of energy about every 3 seconds ! ! !
Just to keep your body warm, keep your breathing going, keep your brain
in tune, and move yourself around !
Enough energy to lift that 30-pound trunk about 6-1/2 feet straight up off
the floor !
1 Calorie = 4184 joules
1 day = 86,400 seconds
