Power Rating = W
Time for which the machine is operating = 2 hours
Time in seconds = 2 × 60 × 60
Time = 7200 seconds
Now, we need to use the formula for work done.
Work done = Power × time
Work done =
Work done = Joules
Hence, work done by the machine in 2 hours is J.
The only definite number we can tell you is that in order to lift
a 100kg box, you have to somehow provide a force of about
980 newtons (about 220 pounds) pointing upward. That's the
weight of the box, and you have to lift with at least that much force
just to get the box off the ground.
After that, the answer to your question is 'YES'. The time it takes
depends on how much force you have available, how far you want
to lift the box, and how fast.
Here are the Physics formulas you have to use:
-- The amount of "Work" you'll do is
(the amount of force you use) times (how far up you lift the box) .
-- The "Power" (amount of watts) you'll use is
(the amount of 'work' you do) divided by (the length of time it takes).
So ...
-- The higher you lift the box, the more 'work' your lift-machine does.
-- The faster the box is lifted, the more 'power' your lift-machine needs.
The force exerted on the rope of the pulley system if the rope is pulled for 24 m in order to raise the mass to the required height is 81.6 N
<u>Explanation:</u>
Efficiency, γ = 64%
mass, m = 78 kg
height, h = 4 m
Force, F = ?
distance of the rope pulled, x = 24 m
We know,
Acceleration due to gravity, g = 9.81 m/s²
Potential energy, PE = mgh = (78) X (9.81) X (4) = 3060.72 joules
Work, W = F X x
F = W/d = (3060.72) / (24) = 127.53 N
However, the efficiency of the pulley system is 64%.
The real force required is F(net) = (127.53) X (0.64) = 81.6 N
Therefore, the force exerted on the rope of the pulley system if the rope is pulled for 24 m in order to raise the mass to the required height is 81.6 N
I'm assuming by the phrasing of your question that you are looking for examples of simple machines that are not wedges.
Well, there are five other simple machines. There is a pulley, lever, screw, wheel and axle, and an inclined plane.
Hope that helped you!