What is 400 Newtons and How Does it Relate to Everyday Life?

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Discussion Overview

The discussion revolves around understanding the concept of 400 Newtons as a measurement of force and its real-world implications. Participants explore various examples and analogies to clarify this concept, particularly in the context of explaining it to a non-scientific audience.

Discussion Character

  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant seeks real-world examples of 400 Newtons, questioning if it relates to scenarios like a brick falling or being hit by a rock.
  • Another participant suggests that 400 N is approximately equivalent to the weight of 40 kg (88 lbs) on Earth, providing a basis for understanding force in terms of weight.
  • There is a mention of an average 8 or 9-year-old boy weighing around 88 pounds, which could serve as a relatable example.
  • One participant proposes that dropping a 90-pound student could illustrate 400 Newtons, but others challenge this by emphasizing that the force experienced would depend on deceleration and suggest alternative explanations.
  • Another participant argues that force should be explained in terms of how hard one needs to push something, using the example of holding a 1 kg object to illustrate 10 Newtons.
  • Clarification is provided that an 88 lbs student standing still exerts a force of 400 N on the ground, contrasting with the idea of dropping a student.

Areas of Agreement / Disagreement

Participants express differing views on how to effectively illustrate the concept of 400 Newtons, with some favoring weight-based examples while others challenge the appropriateness of using extreme scenarios like dropping a student. The discussion remains unresolved regarding the best approach to explain the concept.

Contextual Notes

Participants highlight the importance of understanding the context of force, including factors like deceleration and equilibrium, which may not be fully addressed in the examples provided.

NewtonNewbie
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I'm a middle school history teacher and I have to explain to a group of parents what 400 Newtons is. It's a long story...

I've googled Newtons and understand that they're a measurement of force. It would be great if someone could give me some real world examples of what can produce a force of 400 Newtons.

Is it like a brick falling off a building? Being hit in the head with a rock?

Any help on this would be appreciated as the science teachers in my school are at a loss...
 
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NewtonNewbie said:
I'm a middle school history teacher and I have to explain to a group of parents what 400 Newtons is. It's a long story...

I've googled Newtons and understand that they're a measurement of force. It would be great if someone could give me some real world examples of what can produce a force of 400 Newtons.

Is it like a brick falling off a building? Being hit in the head with a rock?

Any help on this would be appreciated as the science teachers in my school are at a loss...

You can always use the weight equivalent.

400 N is ~ 40 kg on the surface of the Earth (with g ~ 10 m/s^2). This is approximately 88 pounds. So someone who weighs 88 lbs exert a force on the ground equivalent to 400 N.

Zz.
 
So I could say that if I dropped a 90 pound student off the roof of the school, that would be the equivalent of 400 Newtons?
 
NewtonNewbie said:
So I could say that if I dropped a 90 pound student off the roof of the school, that would be the equivalent of 400 Newtons?

No, because the force of the student landing on you would depend on how fast they decelerate. Better to talk about suspending a 90 pound student in your arms or on a rope.

I wonder if the pull from a large dog on a leash would be several hundred N, and if that might be more familiar?
 
NewtonNewbie said:
So I could say that if I dropped a 90 pound student off the roof of the school, that would be the equivalent of 400 Newtons?

I think you've got the wrong idea about force, you don't need rocks falling on peoples heads or students being thown off buildings to expain it. It's best explained simply in terms of how hard you need to "push" something. A force of 10 Newtons for example is the force you'd need to apply to hold approximately 1kg (2.2 pounds) against the force of gravity (at the Earths surface).

For example, if you balance a 1kg object (say bag of flour or whatever) on the palm of your hand then the force with which your hand must push upwards, just to hold it still, is approximately 10 Newtons. Similarly 400 Newtons is equivalent to a mass of about 40kg (88 pounds) in the same situation.
 
NewtonNewbie said:
So I could say that if I dropped a 90 pound student off the roof of the school, that would be the equivalent of 400 Newtons?

No. An 88 lbs student standing still will exert a force (weight) equivalent to 400 N onto the ground. It means that if you put that student on a spring, the spring will experience a force of 400 N on it due to the weight of that student at equilibrium.

Zz.
 
Thanks for all the replies. I think I'll now be able to give a very clear explanation to the parents tonight.
 

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