Prologue TO BIOMECHANICS SECTION 6.1: LINEAR KINETICS

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2. Drive mother. http://www.batesville.k12.in.us/material science/PhyNet/Mechanics/Momentum/drive momentum.htm. 3. Motivation mother. http://www.batesville.k12.in.us/material science/PhyNet/Mechanics/Momentum/drive momentum.htm. 4. Protection OF LINEAR MOMENTUM - RECAP. 5. THE TOTAL MOMENTUM OF A SYSTEM AFTER COLLISION IS EQUAL TO THE TOTAL MOMENTUM OF THE SYSTEM BEFORE COLLISION..

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Slide 1

Prologue TO BIOMECHANICS SECTION 6.1: LINEAR KINETICS

Slide 2

Impulse mother http://www.batesville.k12.in.us/material science/PhyNet/Mechanics/Momentum/drive momentum.htm

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Impulse mother http://www.batesville.k12.in.us/material science/PhyNet/Mechanics/Momentum/motivation momentum.htm

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CONSERVATION OF LINEAR MOMENTUM - RECAP

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THE TOTAL MOMENTUM OF A SYSTEM AFTER COLLISION IS EQUAL TO THE TOTAL MOMENTUM OF THE SYSTEM BEFORE COLLISION.

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M1=90kg V1=6m/sec M2=80kg V2=7m/sec Example: Consider that we have two skaters each heading towards each other. Each of the items has a mass and a speed. Sooner or later in time the bodies impact. Applying the Conservation Principle to this circumstance:

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(m1v1+m2v2) =(m1+m2)V2 (90)(6)+(80)(- 7)=90+80(?) 540-560=170v V=-.12m/sec .12m/sec in course of 80kg player Or IF THE OBJECTS REMAIN IN CONTACT

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IMPULSE(NS) IMPULSE is the utilization of constrain over a specific time J=(F)(T) Force x time

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IMPULSE-MOMENTUM RELATIONSHIP Impulse is in charge of changing the measure of energy. Another method for communicating this is drive brings about an adjustment in force Theoretically this can be best comprehended by looking at the IMPULSE-MOMENTUM RELATIONSHIP

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The Impulse –momentum condition can be effectively gotten from kinematics and Newton's second Law.

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Force/time record for a high vertical hop Shaded region speaks to drive created against floor amid the bounce

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Force/time record for a low vertical hop

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IMPULSE-MOMENTUM RELATIONSHIP Impulse causes an adjustment in energy J=FT M=mv An adjustment in energy can be communicated as  M=m2v2-m1v1 However the mass of a question or body once in a while changes starting with one minute then onto the next  M = m(v2-v1) ?

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If we increment the greatness of the drive what will happen to the force FT=m(v2-v1)

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Momentum will likewise increment and since this expansion will presumably have nothing to so with the mass the outcome will be a comparing increment in the size of the speed. In this way, the change in coming about force is typically connected with an adjustment in the subsequent speed

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How Do We Increase The Impulse So That We Can Increase The Resulting Momentum?

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Theoretically a similar increment in speed ought to have the capacity to be accomplished by applying an expansive constrain for a brief timeframe or a little drive for a drawn out stretch of time. Drive = F t or IMPULSE = F t

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However, In the human body muscles can contract more powerfully over brief timeframes than when they are required to contract all the more gradually imperative to underscore hazardous developments and short take-off circumstances

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Tennis case Suppose that you are playing tennis. You would prefer just not to serve the ball - you need to get a pro! You need to put the ball past your rival before she can respond to it. To do this, you need the ball to have the biggest conceivable speed when it leaves the tennis racket. What does motivation the drive energy condition say in regards to this?

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Since energy relies on upon mass and speed (force = (mass)(velocity)), to state that you need most extreme conceivable speed for the ball is the same as saying that you need the biggest conceivable energy for the ball as it leaves the racket. Presently the ball has basically zero force when you hit it, since it is moving gradually just before the racket hits it. You need to change this force to a substantial energy toward the opposite side of the net. In this way, to state that you need the biggest conceivable force for the ball as it leaves the bat implies that you need the biggest conceivable change in energy for the ball.

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So, to get the biggest conceivable change in energy, we need to apply the biggest conceivable motivation to the ball. Motivation depends straightforwardly on the drive connected and the time the constrain is connected. (Drive = (force)(time)). Thus, to get the biggest conceivable drive you ought to either: apply the biggest conceivable compel apply the constrain for the longest conceivable time or both

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So, swinging harder will hit the ball harder. (Duh?) Certainly, you need to apply greatest constrain by hitting the ball hard. On the off chance that you hit the ball with double the constrain, you will confer double the motivation to the ball. Since motivation = change in energy, this will twofold the ball's adjustment in force. Since energy measures up to mass circumstances speed, multiplying the ball's force will twofold its speed. In any case, on the off chance that you attempt to apply an excessive amount of drive your coordination and timing will endure, and your serve won't be precise - you may even miss the ball!

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You can likewise build the drive on the ball by expanding the time that the racket applies its constrain on the ball - "following through". In the event that you hit the ball for twice as much time, you will give double the motivation to the ball, which implies double the adjustment in force for the ball. In this way, completing is critical. Obviously, on the off chance that you hit the ball hard and complete, you will grant the best motivation to the ball. In the event that you twofold both the constrain and the time, you get four circumstances the motivation, and four circumstances the adjustment in energy!

Slide 24

a similar investigation would apply to hitting a golf ball, baseball, softball - whatever: In rundown: To get the biggest conceivable speed for the ball, you need the biggest conceivable force for the ball, since energy breaks even with mass circumstances speed. To get the biggest conceivable force for the ball, you need to apply the biggest conceivable motivation to the ball, since drive squares with change in energy. To apply the biggest conceivable motivation to the ball, you need to apply the biggest conceivable constrain, or apply a drive for the longest conceivable time, or both.

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JOINT RANGE OF MOTION AND IMPULSE when all is said in done aptitudes which require a maximal utilization of drive likewise require that the joint be traveled through a vast scope of movement R of M impacts time

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IMPULSE AND FORCE ABSORBTION Force retention is the procedure of bit by bit decelerating a moving mass. Extensive strengths should be assimilated amid effect or arriving with a specific end goal to counteract harm or catch or control the protest Another method for wording this is: The question or body has built up a specific measure of force which must be disseminated over a constrained measure of time.

Slide 27

Remember that motivation and energy are personally related. A given motivation will bring about an adjustment in energy. Correspondingly, if a protest or body which is going with a given measure of energy is compelled to diminish the force and in this way, diminish the velocity(as in landing or getting developments) the consequent change will bring about a connected drive.

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Impulse => Ft If the time over which the speed is diminished is little then the drive will be expansive. In the event that the time over which the speed is diminished is expansive then the greatness of the strengths will be little.

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Therefore in the event that we are attempting to assimilate powers we ought to attempt to build the time part of the arrival or a catch however much as could be expected keeping in mind the end goal to diminish the drive per unit time.

Slide 30

Jumping off a seat case Suppose that you will bounce off a seat. When you arrive, you absolutely would prefer not to hurt yourself, yet you realize that the floor needs to apply a constrain on you to stop you. You need this constrain to be as little as could reasonably be expected, in any case. How would you orchestrate it?

Slide 31

First of all, once you hop you are in free fall. You are quickening toward the floor at around 9.8m/s 2 ("g"), and your speed just before you hit the floor essentially relies on upon the stature of the seat. Your energy just before you hit the floor measures up to your mass circumstances your speed. Your mass will be consistent amid the fall, and you can't modify your speed (since air resistance is not going to be an element when you bounce off a seat), so you can't diminish the force you have simply before you hit the floor, either.

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Once the floor stops you, your energy will be zero. So your force will transform from whatever it was simply before you hit (which you can't control) to zero - you have no influence over how much your energy will change when you hit the floor.

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Now, the drive – force condition says that your adjustment in energy will rise to the motivation that the floor applies on you. Your adjustment in energy is dictated by the stature of the seat - you can't change that - so you additionally have no power over the measure of drive that the floor will apply on you. When you cleared out the seat, the motivation that the floor will apply on you was settled.

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FT = change in M FT = mvf –mvi Mvf =0 (body reaching stop/rest)

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It is starting to appear as though you truly don't have a ton of control over this circumstance, isn't that right? (This may clarify why individuals get hurt tumbling down, huh?) The motivation that the floor applies on you to stop you is controlled by your mass and the stature of your hop, and that's it.

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However, the motivation that the floor applies on you relies on upon two things - the drive that the floor applies and the time that it applies it. You DO have some control over the ceasing time! Assume that you flex your knees when you arrive. This expands the time that the floor stops you, subsequently diminishing the compel that the floor needs to apply. The vast majority flex their knees naturally in this circumstance (or possibly they attempted it with bolted knees and got hurt!).

Slide 37

By multiplying the ceasing time, the floor can apply a similar motivation on you with a large portion of the drive. With five circumstances the halting time, the floor needs to apply only one-fifth of the drive to apply a similar motivation on you. Similar standards clarify why it is ideal to fall on a delicate cover or tangle than on a hard floor

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