Chair-lift at constant speed: confusion over passengers per minute, power, etc.

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SUMMARY

The discussion revolves around calculating the power produced by a chair-lift operating at a constant speed, transporting 30 passengers per minute, each with an average mass of 75 kg, over a height of 300 meters in three minutes. The key concepts include the conversion of potential energy (mgh) and kinetic energy (0.5 mv²) to determine the total energy imparted to the passengers. The power output can be derived by converting the total energy from Joules per minute to Joules per second, thus yielding the power in Watts.

PREREQUISITES
  • Understanding of potential energy (mgh) and kinetic energy (0.5 mv²)
  • Basic knowledge of power calculation in physics
  • Familiarity with units of energy (Joules) and power (Watts)
  • Ability to manipulate equations and perform unit conversions
NEXT STEPS
  • Calculate the speed of the chair-lift using the given height and time.
  • Determine the total energy delivered to the passengers using the potential energy formula.
  • Convert the total energy from Joules per minute to Watts for power calculation.
  • Explore similar physics problems involving energy and power for further practice.
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Students studying physics, particularly those focusing on mechanics and energy calculations, as well as educators seeking examples of real-world applications of these concepts.

furor celtica
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Homework Statement



A chair-lift runs at constant speed. Each passenger starts from rest at the lower station, and is delivered to the upper station with the speed of the lift. The lift raises 30 passengers a minute, of average mass 75 kg. The top of the lift is 300 metres higher than the bottom, and the ride takes three minutes. What power do the motors produce?

Homework Equations





The Attempt at a Solution



Firstly this exercise confuses me as it is in the middle of (objectively) much simpler problems such as 'a cyclist maintains a steady speed of x ms^1 when opposed by a force of y Newtons, what power is he producing?'; so I'm guessing there is some generalisation or simplification I'm supposed to make, but I'm just missing it.
I'm not even sure of how to formulate the function of the chair-lift exactly, as in the '30 passengers per minute' and the 'ride takes 3 minutes'.

I just need any suggestion of how to tackle this problem, I'm not looking for a full answer or even an overly-detailed explanation.
 
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furor celtica said:

Homework Statement



A chair-lift runs at constant speed. Each passenger starts from rest at the lower station, and is delivered to the upper station with the speed of the lift. The lift raises 30 passengers a minute, of average mass 75 kg. The top of the lift is 300 metres higher than the bottom, and the ride takes three minutes. What power do the motors produce?

Homework Equations





The Attempt at a Solution



Firstly this exercise confuses me as it is in the middle of (objectively) much simpler problems such as 'a cyclist maintains a steady speed of x ms^1 when opposed by a force of y Newtons, what power is he producing?'; so I'm guessing there is some generalisation or simplification I'm supposed to make, but I'm just missing it.
I'm not even sure of how to formulate the function of the chair-lift exactly, as in the '30 passengers per minute' and the 'ride takes 3 minutes'.

I just need any suggestion of how to tackle this problem, I'm not looking for a full answer or even an overly-detailed explanation.

When people leave a chairlift, they have the speed of the chair lift, so if they started at rest they will have been given a little kinetic energy [0.5 m v2] by the lift. There is enough information given to calculate what the speed is.

Each rider is also raised up quite a distance, so there will be quite a gain in potential energy [mgh].

Now that total amount of energy is given to each passenger, an a lot of them are carried up each minute.

It is quite straight forward to change "Joules per minutes" to "joules per second" and that will be Power!
 
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