The proper power formula is Power = Force in lifting a load * speed of lifting the load.
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How do you calculate power in an elevator?
The work done by the elevator over the 100 meters is easily calculable: W = mgh = (1000)(9.8)(100) = 9.8×105 Joules. The total time of the trip can be calculated from the velocity of the elevator: t = = = 25 s. Thus the average power is given by: P = = = 3.9×104 Watts, or 39 kW.
How do you solve an elevator problem in physics?
support force F = mass x acceleration + weight For a mass m= kg, the elevator must support its weight = mg = Newtons to hold it up at rest. If the acceleration is a= m/s² then a net force= Newtons is required to accelerate the mass. This requires a support force of F= Newtons.
Why do you feel lighter when an elevator goes down physics?
This can also make you feel lighter: when the elevator slows down, you need to slow down with it. But gravity is always pulling you down, so for you to slow down, the floor needs to push up on you less, so gravity can slow you down. Since the floor pushes on you less, you feel lighter.
How do I calculate power?
Power is equal to work divided by time. In this example, P = 9000 J / 60 s = 150 W .
How much power is required to lift a body of 50kg?
(Note: The weight of a 50-kg object is approximately 500 N; it takes 500 N to lift the object up.)
How do you survive a falling elevator physics?
[T]he best way to survive in a falling elevator is to lie down on your back. Sitting is bad but better than standing, because buttocks are nature’s safety foam. Muscle and fat are compressible: they help absorb the G forces of the impact.
Why do you feel heavier when an elevator goes up?
If you stand on a scale in an elevator accelerating upward, you feel heavier because the elevator’s floor presses harder on your feet, and the scale will show a higher reading than when the elevator is at rest. On the other hand, when the elevator accelerates downward, you feel lighter.
What is the apparent weight of a person when an elevator is accelerating upwards?
When the elevator accelerates upward, the apparent weight is greater than the true weight, as Figure 4.16b shows. Conversely, if the elevator accelerates downward, as in part c, the apparent weight is less than the true weight.
How do you calculate the power of a pulley?
It will be necessary to determine force when you want to calculate the work input in a pulley or a system of pulleys. Work is determined by multiplying force by distance traveled: Work (W) = Force (F)X Distance (d) W=Fd.
What is a power unit in an elevator?
An elevator power unit is an integral component found on all types of hydraulic elevators. A power unit serves two critical purposes: it pushes the piston (elevator jack) up and also enables oil to return to the elevator’s tank as a car travels down.
How much power does an elevator use?
Going up uses almost 40 times as much power as going down. Going up 5 floors uses about 500 kilowatt seconds and costs about $0.03. It does not seem to consistently take more power to lift a full elevator than an empty one.
Do you feel heavier when an elevator slows down?
As the elevator reaches a constant speed, you feel normal again. As it stops, you feel heavier for an instant. If you were standing on a scale, it would verify this sensation of an apparent change in weight. What you are feeling is the result of acceleration—speeding up and slowing down—not an actual change in weight.
Why do you feel heavier when you are going down in an elevator or roller coaster?
The Physics of Gravity and Relativity As the elevator starts to move, the floor moves faster and faster in your direction. It pushes up on the bottom of your feet with more force than it would if you were standing still. If you had a scale in that moment, you would weigh more (University of Saskatchewan).
What happens to the weight when elevator slows down?
The normal force is equal to your apparent weight. So, you actually feel a little heavier than usual when the elevator accelerates upward, and lighter than usual when the acceleration is down. In more extreme situations this is much more obvious.
What are the 3 formulas for power?
- P = E t.
- P = W t.
- P = V 2 R.
What are two ways to calculate power?
Power can be calculated in one of two ways. The work-time equation involves dividing the work by the time. The force-velocity equation is multiplying the force by the velocity, as long as the velocity is constant.
What is the formula for power output?
Power measured in watts, symbolized by the letter “W”. Joule’s Law: P = I2R ; P = IE ; P = E2/R.
How much force is required to lift 20 kg?
Answer. Answer: Force is the product of mass and acceleration which in this case is acceleration due to gravity. Thus the work done to lift the load is 196J.
How many watts does it take to lift 100kg?
Final answer: 490 W. (Take g=10 ms−2).
How much energy does it take to lift 1 kg 1 meter?
A joule is the amount of energy needed to exert a force of one newton through one meter. For example, if you lift a one-kilogram weight one meter, then the energy you must expend is: E = Fd = (ma)d = mgd = (1 kg)(9.8m/s2)(1 m) = 9.8 kg m/s2 = 9.8 joules.
Can you survive a 3 story elevator drop?
Falling three storeys (9m): you hit the ground as if you fell 4.7m. Your predicament is upgraded from possibly dead to alive but injured. Expect a broken leg or two, but you’ll live. (Some have suggested lying down in the lift, because it will distribute the force of impact over your whole body.
Can you survive a falling elevator if you jump last second?
The elevator shaft traps air much like a giant air bag, which would soften the blow. But the essence of the original question is still interesting. Jumping at the last second before a plummeting elevator hits the ground would slightly reduce your speed, but not enough to make much of a difference.
Can you survive a falling elevator if you jump?
If the elevator has been falling for a while, then it’s probably moving very fast. If you jump up, then you’ll change your velocity just a little bit. So you’ll be going a tiny bit slower when you hit the ground. So, technically speaking, you would probably not be hurt quite as much.
Does normal force increase when elevator goes up?
From Newton’s second law F=ma, acceleration requires a force proportional to mass. So when the elevator is accelerating upwards, it must not only oppose gravity but provide extra force for the upward acceleration. This requires an increased normal force.