1/4/2024 0 Comments Gravity lab jump![]() In addition to the large takeoff force induced by planting the takeoff leg ahead of the body, there is additional physics to consider as a result of planting the takeoff leg. This is achieved by running with bent legs on the last few steps before takeoff and by running on a curve (which also lowers the center of mass of the high jumper due to the "lean" towards the center of the turn). So at the start of the takeoff stage the center of mass of the high jumper is in a low position and at the end of the takeoff stage it's in a high position. This maximizes the time over which the takeoff force (exerted by the takeoff leg on the ground) is applied, which in turn maximizes the vertical takeoff velocity. This means that the takeoff leg (at the end of the run-up) pushes against the ground harder during takeoff than it would if the jumper is jumping from a standing position.ĭuring the takeoff stage, the vertical range of motion of the center of mass of the high jumper must also be maximized in order to maximize the vertical takeoff velocity. It is believed that this stretching produces a stimulation of the muscles, which in turn allows the foot of the takeoff leg to press harder against the ground". In this process the takeoff leg's knee extensor muscles are stretched. The authors of state: "When the takeoff leg is planted ahead of the body at the end of the run-up, the knee extensor muscles (quadriceps) resist against the flexion of the leg, but the leg is forced to flex anyway, because of the forward momentum of the jumper. ![]() This enables him to maximize the vertical force exerted by his takeoff leg on the ground, which in turn helps maximize his vertical jump velocity. The high jumper must reach a fast running speed before takeoff. The figure below illustrates the run-up and takeoff for the high jump. Optimal high jump technique involves leaning back a bit and planting the takeoff leg ahead of the body, just before the jump. In order to jump as high as possible in the high jump (using the Fosbury Flop), the athlete must maximize his vertical jump velocity at the point of takeoff, while also having sufficient horizontal velocity to carry his body over the bar. Each of the three jump distances are maximized in a similar fashion to how a long jump distance is maximized. Carl Lewis is a well known example of this.Ī more elaborate jumping sport similar to the long jump is the triple jump in which athletes jump three times. Due to the importance of fast running speed in obtaining large long jump distance, it is no surprise that the best sprinters can also be the best long jumpers. This increases h and increases R as a result. To further maximize jumping distance, the long jumper can raise his legs so that he falls further down upon landing. A greater V y increases the time spent airborne which increases the jumping distance R. This is achieved by pushing off the ground with the takeoff leg with as much force as he can. So the only thing the long jumper can do at this point is maximize V y in order to maximize R. At the point of takeoff the horizontal velocity of the long jumper is already established (due to the speed build up during the run). If we reasonably assume that air resistance is negligible, the motion of the center of mass of the long jumper is exactly predicted by the equations for projectile motion, during the airborne phase of the long jump. The center of mass of the long jumper can be treated as a single particle obeying Newton's second law of motion. R is the horizontal jumping distance of the long jumper H is the change in vertical position of the center of mass of the long jumper between the takeoff point and landing point V y is the vertical velocity of the center of mass of the long jumper at the point of takeoff The center of mass is represented by the red dot V x is the horizontal velocity of the center of mass of the long jumper at the point of takeoff. The figure below shows a schematic of the long jump. This is a case of projectile motion in which the maximum distance is achieved by maximizing horizontal velocity and vertical velocity at the point of takeoff. ![]() In order to jump as far as possible in the long jump, the athlete must run as fast as he can and then jump up as high as he can at the point of takeoff. In this page I will mainly discuss the physics of these jumping events. In the high jump the jumping distance is the vertical distance that the athlete clears, and in the long jump the jumping distance is the horizontal distance that the athlete clears. In jumping events such as the long jump and high jump the athlete must propel him or herself into the air with as much speed as possible in order to achieve the maximum jump distance.
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