Power of Gravity on a Moving Mass: Analyzing Mean and Instantaneous Values

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Homework Help Overview

The discussion revolves around a problem in mechanics involving the analysis of mean and instantaneous power developed by gravity on a moving mass. The scenario describes a body of mass m thrown at an angle alpha with an initial velocity v0, and participants are exploring the implications of the displacement vector in relation to gravitational force.

Discussion Character

  • Conceptual clarification, Assumption checking

Approaches and Questions Raised

  • Participants are questioning the relationship between the net displacement of the body and the gravitational force, particularly why the displacement vector is orthogonal to the gravitational force. There is also a focus on defining the start and end points of the body's motion and the implications of these definitions on the problem.

Discussion Status

The discussion is active, with participants seeking clarification on the problem's parameters and assumptions. Some guidance has been offered regarding the assumption that the motion begins and ends on the same plane, but there is no explicit consensus on how this affects the calculations.

Contextual Notes

Participants note the lack of visual aids or diagrams accompanying the problem statement, which may contribute to the confusion regarding the displacement and its direction.

danilo_rj
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A body of mass m is thrown at an angle alpha to the horizontal with the initial velocity v0. Find the mean power developed by gravity over the whole time of motion of the body, and the instantaneous power of gravity as a function of time.

I didn't understand why delta r is orthogonal to mg. Where delta r is the net displacement of the body during time of flight.
 
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Where does the body begin and end its motion? What's the direction of that displacement?
 
what is said in the problem is only this, there is no picture.
 
You are given all the information needed to answer my question.
 
Ok. So I have to suppose that the beginning and the ending of the motion is at a same plane.
 
Exactly.
 

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