That CoM position is total bollocks. It is wildly exaggerated. Also, the claim that passes _under_ the bar is arbitrary and entirely dependent on the individual jumper. Some top jumpers like Kamilla Licwinko, do not arch their backs very much at all. Finally, as a part of the high jump, it has been totally overstated in importance. The claim that it allows jumpers to achieve heights well above their capability is not only wrong - they can either jump that high or they can't - it assumes that this is what is needed to jump high, which is far from the truth. Anyone can arch their back and flop into a pit. Not everyone can jump high. However, the second part makes sense but leaves out the jumper's speed in the final phase of the runup. For reference, some of the data for a jump of around 2.35 for a male jumper between 65 and 70 kg is thus: Velocity at final stride: 7.5-8.0 m/s Foot contact time between 125 and 150 ms Force exerted approx. 650 kg
The video explains it. Another example: the center of mass of a donut is the middle of the hole. To balance things, the center of mass must be alinged with the contact point. To balance a donut, the center of mass (middle of the hole) has to be aligned with the point of contact (ground). The only way to achieve this is by putting the donut upright. There is no other way of balancing a donut with only one point of contact. In the video, the jumper arches the back, shaping it like a donut, and making the center of mass move outside the body.
@@alejandropierolacervantes6426 Hi Alejandro. Thank you for your comment. Yet, having a B.Sc. in Physics, I know more or less what a CoM/CoG is. Actually. the jumper arches his back, shaping it like HALF a donut at most. And in the case of the jumper/video at 1:33, I insist: THERE IS NO WAY the CoM can be under the bar with the whole body except the feet above it.
@@huguesdesesquelles7252 I have not said the center of mass is under the bar, the video says so. I explained that it is possible to move the center of mass outside the body (you should already know that). Maybe this jumper doesn't arch as much as to move the center of mass under the bar, but top athletes do. If not, it would be impossible to jump while almost touching the bar. In this video, if it is not under the bar, it must be close.
@@huguesdesesquelles7252 I agree, having watched the video again, it is quite clear that the center of mass should be represented higher that how it is currently on the video. I guess that the publisher of the video wants to explain that principle, but the chosen video (maybe the only one available to her) is not accurate enough. Anyway, even if a better video could have been chosen, it should be considered as a visual/esquematic represantation (not milimetrically perfect) of the concept.
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Excellent but plz give me detailed explanation with other examples
What is the changes of x? How you calculate that?
His standing hip height (center of gravity) minus the height achieved by the center of gravity (the height of the bar)
Super explanation.
Amazing
That CoM position is total bollocks. It is wildly exaggerated. Also, the claim that passes _under_ the bar is arbitrary and entirely dependent on the individual jumper. Some top jumpers like Kamilla Licwinko, do not arch their backs very much at all. Finally, as a part of the high jump, it has been totally overstated in importance. The claim that it allows jumpers to achieve heights well above their capability is not only wrong - they can either jump that high or they can't - it assumes that this is what is needed to jump high, which is far from the truth. Anyone can arch their back and flop into a pit. Not everyone can jump high.
However, the second part makes sense but leaves out the jumper's speed in the final phase of the runup. For reference, some of the data for a jump of around 2.35 for a male jumper between 65 and 70 kg is thus:
Velocity at final stride: 7.5-8.0 m/s
Foot contact time between 125 and 150 ms
Force exerted approx. 650 kg
E" m,c square 😎😂🤗
urgh the math it hurts
three people cant high jump! XD
CoM under the bar at 1:33 ... are you kidding? (the whole body, except the feet is above the bar)
The video explains it. Another example: the center of mass of a donut is the middle of the hole. To balance things, the center of mass must be alinged with the contact point. To balance a donut, the center of mass (middle of the hole) has to be aligned with the point of contact (ground). The only way to achieve this is by putting the donut upright. There is no other way of balancing a donut with only one point of contact. In the video, the jumper arches the back, shaping it like a donut, and making the center of mass move outside the body.
@@alejandropierolacervantes6426 Hi Alejandro. Thank you for your comment. Yet, having a B.Sc. in Physics, I know more or less what a CoM/CoG is. Actually. the jumper arches his back, shaping it like HALF a donut at most. And in the case of the jumper/video at 1:33, I insist: THERE IS NO WAY the CoM can be under the bar with the whole body except the feet above it.
@@huguesdesesquelles7252 I have not said the center of mass is under the bar, the video says so. I explained that it is possible to move the center of mass outside the body (you should already know that). Maybe this jumper doesn't arch as much as to move the center of mass under the bar, but top athletes do. If not, it would be impossible to jump while almost touching the bar. In this video, if it is not under the bar, it must be close.
@@huguesdesesquelles7252 I agree, having watched the video again, it is quite clear that the center of mass should be represented higher that how it is currently on the video. I guess that the publisher of the video wants to explain that principle, but the chosen video (maybe the only one available to her) is not accurate enough. Anyway, even if a better video could have been chosen, it should be considered as a visual/esquematic represantation (not milimetrically perfect) of the concept.
@@alejandropierolacervantes6426 Hi Alejandro, all clear then, and thanks again for commenting