Calculating Mass from Acceleration and Net Force

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Homework Help Overview

The discussion revolves around calculating the mass of a high jumper based on their acceleration and the net force exerted by a foam pit during landing. The problem involves concepts from dynamics and kinematics.

Discussion Character

  • Exploratory, Assumption checking, Problem interpretation

Approaches and Questions Raised

  • Participants are considering how to relate the distance the pit compresses and the jumper's velocity to find mass, with some uncertainty about whether to multiply or divide these values. There is also a focus on the implications of the calculated mass values.

Discussion Status

Some participants have provided guidance on applying Newton's second law and have prompted the original poster to clarify their calculations. Multiple interpretations of the problem are being explored, particularly regarding the correct approach to find the mass.

Contextual Notes

There is uncertainty about the correct method to apply in the calculations, and participants are questioning the assumptions made regarding the values used in the calculations.

MissFortune
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This was the original question: A high jumper falling a 3.9 m/s, lands on a foam pit and comes to rest, compressing the pit a distance of 0.43 m. If the pit is able to exert an average fource of -1100 N on the high jumper in breaking the fall, what is the jumper's mass?
But I am not sure if I am supposed to multiply or divide 0.43m and 3.9 m/s
Ive narrowed the answer down to either 1845 kg or 121 kg.
 
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Ive narrowed the answer down to either 1845 kg or 121 kg.

Well, 1845kg is about 4000lbs.. whereas 121kg is about 260lbs..
 
Ive been leaning towards 121kg mainly because of that, but I just wanted to be sure.
 
Show your work and I can look over it.
 
MissFortune said:
But I am not sure if I am supposed to multiply or divide 0.43m and 3.9 m/s
Ive narrowed the answer down to either 1845 kg or 121 kg.
Sounds like you're guessing?

(1) What's the acceleration?
(2) Apply Newton's 2nd law to find the mass. (Use the net force.)
 

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