11. Newton’s third law - Revision history

Ian at 13:29, 8 March 2010

Ian — Mon, 08 Mar 2010 13:29:00 GMT

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	== '''Key Points''' ==		== '''Key Points''' ==

-	Newton’s third law is often stated ~~in the form below,~~	+	Newton’s third law is often stated as follows.

-	For every action, there is an equal but opposite reaction.	+	For every action force , there is an equal but opposite reaction force.

	The examples below illustrate how this law can be applied.		The examples below illustrate how this law can be applied.

Ian at 18:01, 16 February 2010

Ian — Tue, 16 Feb 2010 18:01:00 GMT

←Older revision		Revision as of 18:01, 16 February 2010
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-	11. Newton’s Third Law

-	Key Points	+	== '''Key Points''' ==

	Newton’s third law is often stated in the form below,		Newton’s third law is often stated in the form below,

-	For every action, there is an equal but opposite reaction.	+	For every action, there is an equal but opposite reaction.

	The examples below illustrate how this law can be applied.		The examples below illustrate how this law can be applied.
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	The diagrams show these normal reaction forces. There is one normal reaction for each foot.		The diagrams show these normal reaction forces. There is one normal reaction for each foot.
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	[[Image:TF11.1.GIF]]		[[Image:TF11.1.GIF]]
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	In this example it is important to note that this example does not involve the weight of the person, although		In this example it is important to note that this example does not involve the weight of the person, although
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	A second example concerns an object that is falling vertically towards the earth. The earth exerts a downward force on the object. This is known as the weight of the object. The object also exerts an upward force of equal magnitude on the earth. These forces are shown in the exaggerated diagram shown below.		A second example concerns an object that is falling vertically towards the earth. The earth exerts a downward force on the object. This is known as the weight of the object. The object also exerts an upward force of equal magnitude on the earth. These forces are shown in the exaggerated diagram shown below.
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	[[Image:TF11.2.GIF]]		[[Image:TF11.2.GIF]]
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Ian at 08:15, 2 September 2009

Ian — Wed, 02 Sep 2009 08:15:05 GMT

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	11. Newton’s Third Law		11. Newton’s Third Law

Ian at 08:14, 2 September 2009

Ian — Wed, 02 Sep 2009 08:14:11 GMT

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-	{{Selected tab\|[[2. ~~Introduction to force and gravity~~\|Theory]]}}	+	{{Selected tab\|[[11. Newton’s third law\|Theory]]}}
-	{{Not selected tab\|[[2. Exercises\|Exercises]]}}	+	{{Not selected tab\|[[11. Exercises\|Exercises]]}}
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Ian at 07:56, 2 September 2009

Ian — Wed, 02 Sep 2009 07:56:57 GMT

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		+	{{Not selected tab\|[[2. Exercises\|Exercises]]}}
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	11. Newton’s Third Law		11. Newton’s Third Law

Ian at 09:32, 28 August 2009

Ian — Fri, 28 Aug 2009 09:32:52 GMT

←Older revision		Revision as of 09:32, 28 August 2009
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	The examples below illustrate how this law can be applied.		The examples below illustrate how this law can be applied.

-	Example 11.1	+
		+	'''[[Example 11.1]]'''
		+
	If you stand on the ground, your feet push down on the ground. In response to this the ground exerts an upward force on each of your feet. Both of these forces are normal reaction forces.		If you stand on the ground, your feet push down on the ground. In response to this the ground exerts an upward force on each of your feet. Both of these forces are normal reaction forces.

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-		+	[[Image:TF11.1.GIF]]
-		+


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	.		.

-	Example 11.2
-	A second example concerns an object that is falling vertically towards the earth. The earth exerts a downward force on the object. This is known as the weight of the object. The object also exerts an upward force of equal magnitude on the earth. These forces are shown in the exaggerated diagram shown below.

		+	'''[[Example 11.2]]'''

		+	A second example concerns an object that is falling vertically towards the earth. The earth exerts a downward force on the object. This is known as the weight of the object. The object also exerts an upward force of equal magnitude on the earth. These forces are shown in the exaggerated diagram shown below.



		+
		+	[[Image:TF11.2.GIF]]


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-	Example 11.3	+	'''[[Example 11.3]]'''
-	As a final example consider a motorboat towing a dinghy. The motorboat exerts a forward force on the dinghy through the tow rope. Te dinghy in turn exerts a backwards force on the boat through the tow rope. The forces are equal in magnitude but opposite in direction. The diagram shows these forces.	+
		+	As a final example consider a motorboat towing a dinghy. The motorboat exerts a forward force on the dinghy through the tow rope. The dinghy in turn exerts a backwards force on the boat through the tow rope. The forces are equal in magnitude but opposite in direction. The diagram shows these forces.
		+
		+	[[Image:TF11.3.GIF]]

Ian: New page: 11. Newton’s Third Law Key Points Newton’s third law is often stated in the form below, For every action, there is an equal but opposite reaction. The examples below illustrate ho...

Ian — Fri, 28 Aug 2009 09:20:06 GMT

New page: 11. Newton’s Third Law Key Points Newton’s third law is often stated in the form below, For every action, there is an equal but opposite reaction. The examples below illustrate ho...

New page

11. Newton’s Third Law

Key Points

Newton’s third law is often stated in the form below,

For every action, there is an equal but opposite reaction.

The examples below illustrate how this law can be applied.

Example 11.1
If you stand on the ground, your feet push down on the ground. In response to this the ground exerts an upward force on each of your feet. Both of these forces are normal reaction forces.

The diagrams show these normal reaction forces. There is one normal reaction for each foot.

In this example it is important to note that this example does not involve the weight of the person, although
<math>W={{R}_{1}}+{{R}_{2}}</math>
.

Example 11.2
A second example concerns an object that is falling vertically towards the earth. The earth exerts a downward force on the object. This is known as the weight of the object. The object also exerts an upward force of equal magnitude on the earth. These forces are shown in the exaggerated diagram shown below.

Example 11.3
As a final example consider a motorboat towing a dinghy. The motorboat exerts a forward force on the dinghy through the tow rope. Te dinghy in turn exerts a backwards force on the boat through the tow rope. The forces are equal in magnitude but opposite in direction. The diagram shows these forces.

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-	{{Not selected tab\|[[2. Exercises\|Exercises]]}}	+	{{Not selected tab\|[[11. Exercises\|Exercises]]}}
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