Terminal Velocity and Friction Due to Air - Revision history

Cshimkus3: /* Connectedness */

2015-11-30T15:31:05Z

Connectedness

← Older revision		Revision as of 11:31, 30 November 2015
Line 70:		Line 70:
	==Connectedness==		==Connectedness==
	#How is this topic connected to something that you are interested in?		#How is this topic connected to something that you are interested in?
			I have always been interested in skydiving and this topic is a vital concept for the spot. Just as in the example above, the way a skydiver positions their body determines how fast they will fall.
	#How is it connected to your major?		#How is it connected to your major?
	#Is there an interesting industrial application?		#Is there an interesting industrial application?

Cshimkus3: /* Examples */

2015-11-30T15:27:37Z

Examples

← Older revision		Revision as of 11:27, 30 November 2015
Line 65:		Line 65:

	'''Heat of Spacecraft''': Think of a spacecraft re-entering the Earth's atmosphere. How would the engineers designing that spacecraft need to determine the temperature that the space craft material needs to withstand. Well, these engineers could use the energy principle and the specific heat of the building material to do so. By calculating the terminal velocity, the initial potential and kinetic energy of the space craft when it enters the Earth's gravitational pull, and then graphing all the energy as at the space ship plummets to Earth's surface, these engineers can determine the heat this building material must be able to withstand.		'''Heat of Spacecraft''': Think of a spacecraft re-entering the Earth's atmosphere. How would the engineers designing that spacecraft need to determine the temperature that the space craft material needs to withstand. Well, these engineers could use the energy principle and the specific heat of the building material to do so. By calculating the terminal velocity, the initial potential and kinetic energy of the space craft when it enters the Earth's gravitational pull, and then graphing all the energy as at the space ship plummets to Earth's surface, these engineers can determine the heat this building material must be able to withstand.

			[[File:Reentry2.jpg\|thumb\|center\|600x310px]]

	==Connectedness==		==Connectedness==

Cshimkus3 at 15:24, 30 November 2015

2015-11-30T15:24:40Z

← Older revision		Revision as of 11:24, 30 November 2015
Line 60:		Line 60:
	===Examples===		===Examples===

	'''Skydiver''': Think of a free-falling skydiver. When he/she is falling with their arms and legs stretched out like a star, they will accelerate until he or she reaches their terminal velocity. Now, what would happen if the free-faller pulled in his/her arms and legs and leans forward so that their body is more parallel with their free-fall? From our definition of terminal velocity defined above, we know that this speed is inversely dependent on the surface area of the falling object. So, we can infer that the skydiver would speed up, because when he/she bring their arms and legs in, they decrease their surface area perpendicular to the fall and therefor increase their terminal velocity.		'''Skydiver''': Think of a free-falling skydiver. When he/she is falling with their arms and legs stretched out like a star, they will accelerate until he or she reaches their terminal velocity. Now, what would happen if the free-faller pulled in his/her arms and legs and leans forward so that their body is more parallel with their free-fall? From our definition of terminal velocity defined above, we know that this speed is inversely dependent on the surface area of the falling object. So, we can infer that the skydiver would speed up, because when he/she bring their arms and legs in, they decrease their surface area perpendicular to the fall and therefor increase their terminal velocity.

			[[File:Skydiver2.jpg\|thumb\|center\|600x310px]]

	'''Heat of Spacecraft''': Think of a spacecraft re-entering the Earth's atmosphere. How would the engineers designing that spacecraft need to determine the temperature that the space craft material needs to withstand. Well, these engineers could use the energy principle and the specific heat of the building material to do so. By calculating the terminal velocity, the initial potential and kinetic energy of the space craft when it enters the Earth's gravitational pull, and then graphing all the energy as at the space ship plummets to Earth's surface, these engineers can determine the heat this building material must be able to withstand.		'''Heat of Spacecraft''': Think of a spacecraft re-entering the Earth's atmosphere. How would the engineers designing that spacecraft need to determine the temperature that the space craft material needs to withstand. Well, these engineers could use the energy principle and the specific heat of the building material to do so. By calculating the terminal velocity, the initial potential and kinetic energy of the space craft when it enters the Earth's gravitational pull, and then graphing all the energy as at the space ship plummets to Earth's surface, these engineers can determine the heat this building material must be able to withstand.

Cshimkus3: /* Examples */

2015-11-30T15:19:47Z

Examples

← Older revision		Revision as of 11:19, 30 November 2015
Line 60:		Line 60:
	===Examples===		===Examples===

	'''~~Reversible process~~''': ~~Ideally forcing~~ a ~~flow through~~ a ~~constricted pipe~~, ~~where there are no boundary layers~~. As the ~~flow moves through~~ the ~~constriction~~, the ~~pressure~~, ~~volume~~ and ~~temperature change~~, ~~but~~ they ~~return to~~ their ~~normal values once they hit the downstream. This return~~ to the ~~variables' original values allows there to be no change in entropy~~. ~~It is often known as an isentropic process.~~		'''Skydiver''': Think of a free-falling skydiver. When he/she is falling with their arms and legs stretched out like a star, they will accelerate until he or she reaches their terminal velocity. Now, what would happen if the free-faller pulled in his/her arms and legs and leans forward so that their body is more parallel with their free-fall? From our definition of terminal velocity defined above, we know that this speed is inversely dependent on the surface area of the falling object. So, we can infer that the skydiver would speed up, because when he/she bring their arms and legs in, they decrease their surface area perpendicular to the fall and therefor increase their terminal velocity.

	'''~~Irreversible process~~''': ~~When~~ a ~~hot object~~ and ~~cold object are put in contact with each other, eventually~~ the heat ~~from~~ the ~~hot object will transfer~~ to the ~~cold object~~ and the ~~two will reach~~ the ~~same temperature~~ and ~~stay constant~~ at ~~that temperature~~, ~~reaching equilibrium. However, once those objects are separated, they will remain at that equilibrium temperature until something else acts upon it. The objects do not go back~~ to ~~their original temperatures so there is a change in entropy~~.		'''Heat of Spacecraft''': Think of a spacecraft re-entering the Earth's atmosphere. How would the engineers designing that spacecraft need to determine the temperature that the space craft material needs to withstand. Well, these engineers could use the energy principle and the specific heat of the building material to do so. By calculating the terminal velocity, the initial potential and kinetic energy of the space craft when it enters the Earth's gravitational pull, and then graphing all the energy as at the space ship plummets to Earth's surface, these engineers can determine the heat this building material must be able to withstand.

	==Connectedness==		==Connectedness==

Cshimkus3: /* A Graphical Interpretation */

2015-11-30T14:47:02Z

A Graphical Interpretation

← Older revision		Revision as of 10:47, 30 November 2015
Line 47:		Line 47:
	D) .5 kg Feather Falling in Air		D) .5 kg Feather Falling in Air

	[[File:~~Velocity_ball_air~~.~~jpg~~\|thumb\|center\|1100x510px]]		[[File:Velocity_feather_air.png\|thumb\|center\|1100x510px]]

	E) Energy of Ball Falling in Vacuum: Energy vs Time		E) Energy of Ball Falling in Vacuum: Energy vs Time
	(yellow=total, red=kinetic, blue=thermal, cyan=potential)		(yellow=total, red=kinetic, blue=thermal, cyan=potential)

	[[File:~~Velocity_ball_air~~.~~jpg~~\|thumb\|center\|1100x510px]]		[[File:Energy_vacuum.png\|thumb\|center\|1100x510px]]

	F) Energy of Ball Falling in Air		F) Energy of Ball Falling in Air

	[[File:~~Velocity_ball_air~~.~~jpg~~\|thumb\|center\|1100x510px]]		[[File:Energy_air.png\|thumb\|center\|1100x510px]]

	===Examples===		===Examples===

Cshimkus3: /* A Graphical Interpretation */

2015-11-30T14:44:23Z

A Graphical Interpretation

← Older revision		Revision as of 10:44, 30 November 2015
Line 34:		Line 34:

	A) 5 kg Ball Falling in Vacuum: Velocity vs Height		A) 5 kg Ball Falling in Vacuum: Velocity vs Height

			[[File:Velocity_ball_vacuum.png\|thumb\|center\|1100x510px]]

	B) 5 kg Ball Falling in Air		B) 5 kg Ball Falling in Air
Line 40:		Line 42:

	C) .5 kg Feather Falling in Vacuum		C) .5 kg Feather Falling in Vacuum

			[[File:Velocity_ball_vacuum.png\|thumb\|center\|1100x510px]]

	D) .5 kg Feather Falling in Air		D) .5 kg Feather Falling in Air

			[[File:Velocity_ball_air.jpg\|thumb\|center\|1100x510px]]

	E) Energy of Ball Falling in Vacuum: Energy vs Time		E) Energy of Ball Falling in Vacuum: Energy vs Time
	(yellow=total, red=kinetic, blue=thermal, cyan=potential)		(yellow=total, red=kinetic, blue=thermal, cyan=potential)

			[[File:Velocity_ball_air.jpg\|thumb\|center\|1100x510px]]

	F) Energy of Ball Falling in Air		F) Energy of Ball Falling in Air

			[[File:Velocity_ball_air.jpg\|thumb\|center\|1100x510px]]

	===Examples===		===Examples===

Cshimkus3: /* A Graphical Interpretation */

2015-11-30T14:42:06Z

A Graphical Interpretation

← Older revision		Revision as of 10:42, 30 November 2015
Line 37:		Line 37:
	B) 5 kg Ball Falling in Air		B) 5 kg Ball Falling in Air

	[[File:~~Velocity ball air~~.~~png~~\|~~native~~\|center]]		[[File:Velocity_ball_air.jpg\|thumb\|center\|1100x510px]]

	C) .5 kg Feather Falling in Vacuum		C) .5 kg Feather Falling in Vacuum

Cshimkus3: /* A Graphical Interpretation */

2015-11-30T14:38:40Z

A Graphical Interpretation

← Older revision		Revision as of 10:38, 30 November 2015
Line 37:		Line 37:
	B) 5 kg Ball Falling in Air		B) 5 kg Ball Falling in Air

	[[File:Velocity ball air.png]]		[[File:Velocity ball air.png\|native\|center]]

	C) .5 kg Feather Falling in Vacuum		C) .5 kg Feather Falling in Vacuum

Cshimkus3: /* A Graphical Interpretation */

2015-11-30T14:31:25Z

A Graphical Interpretation

← Older revision		Revision as of 10:31, 30 November 2015
Line 36:		Line 36:

	B) 5 kg Ball Falling in Air		B) 5 kg Ball Falling in Air

			[[File:Velocity ball air.png]]

	C) .5 kg Feather Falling in Vacuum		C) .5 kg Feather Falling in Vacuum
Line 44:		Line 46:
	(yellow=total, red=kinetic, blue=thermal, cyan=potential)		(yellow=total, red=kinetic, blue=thermal, cyan=potential)

	F) Energy of Ball Falling in Air		F) Energy of Ball Falling in Air


	===Examples===		===Examples===

Cshimkus3: /* Where does that energy go? */

2015-11-30T14:29:30Z

Where does that energy go?

← Older revision		Revision as of 10:29, 30 November 2015
Line 27:		Line 27:
	==Where does that energy go?==		==Where does that energy go?==

	~~How do~~ we ~~visualize or predict using~~ this ~~topic~~. ~~Consider embedding some vpython code here [https://trinket~~.~~io/glowscript/31d0f9ad9e Teach hands-on~~ with ~~GlowScript]~~		When we think of the energy of a falling object from the stance of a point-particle system, it will seem that some of the energy will disappear. When a falling object reaches terminal velocity, its kinetic energy remains constant while its potential energy due to gravity decreases. So, where does this energy go? We can now think of the falling object as an extended system and see that this energy get converted to internal energy as heat. The friction between the air and the falling object creates heat that takes the form of the ''lost'' energy. In a vacuum, this would not happen. The gravitational and kinetic energy of an object in a vacuum would vary inversely with one another.

	===A Graphical Interpretation===		===A Graphical Interpretation===

	The ~~first law of thermodynamics defines~~ the ~~internal~~ energy (E) ~~as equal to the difference between heat transfer (Q~~) ~~''into'' a system and work (W~~) ~~''done by'' the system~~. ~~Heat removed from a system would be given a negative sign and heat applied to the system would be given a positive sign~~. ~~Internal energy can be converted into other types~~ of ~~energy because it acts like potential energy. Heat and work~~, ~~however~~, ~~cannot be stored or conserved independently because they depend on the process. This allows for many different possible states~~ of ~~a system to exist. There can be a process known as the adiabatic process~~ in which there is no heat transfer. This occurs when a system is full insulated from the outside environment. The implementation of this law also brings about another useful state variable, '''enthalpy'''.		The following graphs will help you better understand the motion and energy relationships of a falling object.

			A) 5 kg Ball Falling in Vacuum: Velocity vs Height

			B) 5 kg Ball Falling in Air

			C) .5 kg Feather Falling in Vacuum

			D) .5 kg Feather Falling in Air

			E) Energy of Ball Falling in Vacuum: Energy vs Time
			(yellow=total, red=kinetic, blue=thermal, cyan=potential)

			F) Energy of Ball Falling in Air


Line 38:		Line 51:
	'''Reversible process''': Ideally forcing a flow through a constricted pipe, where there are no boundary layers. As the flow moves through the constriction, the pressure, volume and temperature change, but they return to their normal values once they hit the downstream. This return to the variables' original values allows there to be no change in entropy. It is often known as an isentropic process.		'''Reversible process''': Ideally forcing a flow through a constricted pipe, where there are no boundary layers. As the flow moves through the constriction, the pressure, volume and temperature change, but they return to their normal values once they hit the downstream. This return to the variables' original values allows there to be no change in entropy. It is often known as an isentropic process.

	'''Irreversible process''': When a hot object and cold object are put in contact with each other, eventually the heat from the hot object will transfer to the cold object and the two will reach the same temperature and stay constant at that temperature, reaching equilibrium. However, once those objects are separated, they will remain at that equilibrium temperature until something else acts upon it. The objects do not go back to their original temperatures so there is a change in entropy.		'''Irreversible process''': When a hot object and cold object are put in contact with each other, eventually the heat from the hot object will transfer to the cold object and the two will reach the same temperature and stay constant at that temperature, reaching equilibrium. However, once those objects are separated, they will remain at that equilibrium temperature until something else acts upon it. The objects do not go back to their original temperatures so there is a change in entropy.

	==Connectedness==		==Connectedness==