Simple Energy Problem Im missing something

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Homework Help Overview

The problem involves a coyote falling from a height of 30.0m and impacting the ground, creating a dent of 0.420m. The discussion centers around calculating the force exerted by the ground on the coyote upon impact, considering energy transformations and forces involved during the collision.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants discuss the relationship between potential energy, kinetic energy, and the forces acting on the coyote during the impact. Questions arise about the nature of the force exerted by the ground and whether it can be simplified to just the weight of the coyote.

Discussion Status

The discussion is ongoing, with participants exploring different interpretations of the forces at play. Some guidance has been offered regarding the relationship between kinetic energy and the work done by the ground force, but clarity on the exact nature of the force remains a point of confusion.

Contextual Notes

Participants are navigating assumptions about energy conservation and the dynamics of the impact, with an emphasis on understanding the forces involved rather than deriving a final answer.

Stevedye56
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The coyote, whose mass is 20.0kg, is chasing the roadrunner when the coyote accidentally runs off the edge of a cliff and plummets to the ground 30.0m below. What force does the ground exert on the coyote as he makes a coyote-shaped dent .420m deep in the ground?

I know that he hits the ground with a force of 6,000J becasue the PE=mgh at the top, Assuming that none of his energy is lost to air resistance he will hit the ground with that same force because all of the potential energy will be converted into kinetic energy. I am just not sure how to get the force. I know F=ma but that seems just to simple.


Any help at all will be appreciated.

Thanks for looking,

Steve
 
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Stevedye56 said:
What force does the ground exert on the coyote as he makes a coyote-shaped dent .420m deep in the ground?

Do you mean, what is the force which the ground exerts on the coyote while he's been slammed into the ground? If so, use the fact that the change of kinetic energy from the position above the ground to the position when the coyote is stuck in the ground (where his speed = 0) equals the sum of work of gravity (i.e. the coyote's weight) and the work of the force which the ground exerts on him, along the displacement of 0.42 [m]. I hope I didn't miss something.
 
radou said:
Do you mean, what is the force which the ground exerts on the coyote while he's been slammed into the ground? If so, use the fact that the change of kinetic energy from the position above the ground to the position when the coyote is stuck in the ground (where his speed = 0) equals the sum of work of gravity (i.e. the coyote's weight) and the work of the force which the ground exerts on him, along the displacement of 0.42 [m]. I hope I didn't miss something.


Im not sure i understand what your are saying. Are you saying that the force is just mg? Or am i not reading correctly
 
Stevedye56 said:
Im not sure i understand what your are saying. Are you saying that the force is just mg? Or am i not reading correctly

No, the force is not just mg. While being slammed into the ground, the forces acting on the coyote are gravity, and the force which the ground exerts on the coyote (in the opposite direction than gravity), which is the force you need to find.
 

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