Horsepower to G-Force: Calculations for a Tetherball

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Discussion Overview

The discussion centers around calculating the horsepower required to accelerate a tetherball to a speed of 36 miles per hour and determining the maximum g-force experienced at that speed and during deceleration to zero. The conversation involves the properties of the tetherball system, including the pole, string, and ball, and addresses the need for specific parameters in the calculations.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Debate/contested

Main Points Raised

  • One participant notes that in the absence of friction or drag, any non-zero amount of power will eventually achieve the desired speed for the tetherball.
  • Another participant emphasizes the importance of specifying a time frame for calculations involving horsepower and acceleration, stating that power is defined in terms of energy spent over time.
  • A different participant points out the need for consistent units, converting 36 mph to 57.6 kilometers per hour, and discusses how horsepower relates to lifting power and acceleration.
  • One participant mentions that to calculate the energy required to accelerate a mass to a certain velocity, one must use the kinetic energy formula, and that dividing this energy by the time taken will yield the average horsepower needed.
  • There is a repeated emphasis on the necessity of specifying time to determine acceleration or deceleration accurately.

Areas of Agreement / Disagreement

Participants generally agree on the need for specific parameters such as time and consistent units in the calculations. However, there are multiple competing views regarding the implications of power and acceleration, and the discussion remains unresolved on the exact calculations needed.

Contextual Notes

Limitations include the lack of specified time frames for acceleration and deceleration, which affects the ability to determine g-forces accurately. There is also a dependence on the definitions of horsepower and energy in the context of the calculations.

milton3
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This question is for background information on a start up technology.

Starting with the tetherball analogy: Assuming the force would be applied to spinning the base of the tetherball pole what amount of horse power is needed to get the tetherball up to a speed of 36 miles per hour with these properties; tetherball poll (2 kilograms), string (1 meter) and ball (1.9 kilograms)?

At constant speed what is the max g-force?

If the process was reversed, 36 mph to zero, what would be the max g-force?
 
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If there's no friction or drag, then any (non-zero) amount of power will eventually get the ball up to speed.
 
milton3 said:
This question is for background information on a start up technology.

Starting with the tetherball analogy: Assuming the force would be applied to spinning the base of the tetherball pole what amount of horse power is needed to get the tetherball up to a speed of 36 miles per hour with these properties; tetherball poll (2 kilograms), string (1 meter) and ball (1.9 kilograms)?

At constant speed what is the max g-force?

If the process was reversed, 36 mph to zero, what would be the max g-force?

You should at least keep the units the same, 36 mph is 57.6 Kilometers/hour.
The other problem is you did not specify a time frame. Horsepower and such in terms of lifting power is defined as the ability to move or lift straight up 555 pounds (252.27 kg) one foot (304 mm, 30.4 cm) in one second. So if you could apply one hp to 555 pounds in space as an acceleration it would give 1/32 of a G, so 32 hp would accelerate 555 pounds in space at one G.

You need to be more specific about your units and such. Try it again.
 
Whenever you are talking power or acceleration, you need to set a time restriction. Power is the amount of energy spent in a given time and acceleration is the amount of velocity variation in a given time.

milton3 said:
Starting with the tetherball analogy: Assuming the force would be applied to spinning the base of the tetherball pole what amount of horse power is needed to get the tetherball up to a speed of 36 miles per hour with these properties; tetherball poll (2 kilograms), string (1 meter) and ball (1.9 kilograms)?

To get a mass m to go from 0 to velocity v, you need an amount of energy equal to http://en.wikipedia.org/wiki/Kinetic_energy#Newtonian_kinetic_energy". If you divide this amount of energy by the the time taken to reach v, you will get the average horsepower needed.

milton3 said:
At constant speed what is the max g-force?

Technically, http://en.wikipedia.org/wiki/G-force" principle.

milton3 said:
If the process was reversed, 36 mph to zero, what would be the max g-force?

Here you have the speed difference, but you don't specified the time, so we cannot determine the acceleration (or deceleration, in this case).
 
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