# Force of impact question

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#### willpower

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##### Force of impact question
« on: 27/04/2012 15:51:42 »
I drop a 1kg weight from a meter in height and it decelerates to a stop in 0.1 of a meter (total distance travelled 1.1 meters)
What force is applied to the impact object?
What force is applied to the falling object? (assuming no deformation)
All assuming no air resistance and no bouncing

#### Æthelwulf

• Sr. Member
• 358
##### Re: Force of impact question
« Reply #1 on: 27/04/2012 18:33:28 »
Well, what equations have you learned for the question? I assume this is homework. I'll steer you in the right direction:

$$Mgh = \frac{1}{2} Mv^2 - \frac{1}{2}Mu^2$$

The force is $$F=Mg$$ and weight is also a force $$W = Mg$$.
« Last Edit: 28/04/2012 01:48:01 by Æthelwulf »

#### Æthelwulf

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##### Re: Force of impact question
« Reply #2 on: 27/04/2012 18:50:33 »
I drop a 1kg weight from a meter in height and it decelerates to a stop in 0.1 of a meter (total distance travelled 1.1 meters)
What force is applied to the impact object?
What force is applied to the falling object? (assuming no deformation)
All assuming no air resistance and no bouncing

Why is your question expressing weight in kilograms, that is the unit for mass. Weight is expressed traditionally in Newtons?

#### imatfaal

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##### Re: Force of impact question
« Reply #3 on: 27/04/2012 18:59:00 »
I drop a 1kg weight from a meter in height and it decelerates to a stop in 0.1 of a meter (total distance travelled 1.1 meters)
What force is applied to the impact object?
What force is applied to the falling object? (assuming no deformation)
All assuming no air resistance and no bouncing

Why is your question expressing weight in kilograms, that is the unit for mass. Weight is expressed traditionally in Newtons?

http://en.wiktionary.org/wiki/weight

You should check out def no.s 2,3 &5.  Weight in the OP is being used as a concrete noun - ie a lump of metal of known mass.
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#### Æthelwulf

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##### Re: Force of impact question
« Reply #4 on: 27/04/2012 19:26:01 »
I drop a 1kg weight from a meter in height and it decelerates to a stop in 0.1 of a meter (total distance travelled 1.1 meters)
What force is applied to the impact object?
What force is applied to the falling object? (assuming no deformation)
All assuming no air resistance and no bouncing

Why is your question expressing weight in kilograms, that is the unit for mass. Weight is expressed traditionally in Newtons?

http://en.wiktionary.org/wiki/weight

You should check out def no.s 2,3 &5.  Weight in the OP is being used as a concrete noun - ie a lump of metal of known mass.

Oh right. Ok.

#### Æthelwulf

• Sr. Member
• 358
##### Re: Force of impact question
« Reply #5 on: 27/04/2012 19:32:02 »
I drop a 1kg weight from a meter in height and it decelerates to a stop in 0.1 of a meter (total distance travelled 1.1 meters)
What force is applied to the impact object?
What force is applied to the falling object? (assuming no deformation)
All assuming no air resistance and no bouncing

Why is your question expressing weight in kilograms, that is the unit for mass. Weight is expressed traditionally in Newtons?

http://en.wiktionary.org/wiki/weight

You should check out def no.s 2,3 &5.  Weight in the OP is being used as a concrete noun - ie a lump of metal of known mass.

Oh right. Ok.

So really

1kilogram of mass  as we know is 9.81 newtons thus I suppose, 1kg = 9.81 newtons and since 1 newton is 0.101971621 kilogram of force then 1 kilogram of force is 9.80665 newton.

#### Geezer

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##### Re: Force of impact question
« Reply #6 on: 27/04/2012 20:53:34 »

1kilogram of mass  as we know is 9.81 newtons thus I suppose, 1kg = 9.81 newtons and since 1 newton is 0.101971621 kilogram of force then 1 kilogram of force is 9.80665 newton.

1kg (mass) exerts a force of around 9.81N in standard Earth gravity (your measured force might vary).

There ain'ta no sanity clause, and there ain'ta no centrifugal force æther.