The picture below shows a snowboarder executing a purely carved turn. Carved Turns The physics behind carving is different from the physics behind skidding. Unlike skidding where a snowboarder pivots into a turn, a carved turn is initiated by the snowboarder easing into the turn.
Snowboards are manufactured with a sidecut on both sides. The amount of sidecut determines the curvature of the snowboard, which is of a certain constant radius along the sidecut edge. The figure below illustrates a sidecut snowboard, where R SC is the sidecut radius. It affects the physics by influencing the radius of purely carved turns, as will be discussed.
A purely carved turn can be done with a snowboard that is flat on the snow or tilted at an angle to the snow. This is discussed in more detail in the section on how to prevent snowboard slippage. When the snowboard is flat on the snow, a purely carved turn is executed when the radius of the turn R T equals the sidecut radius R SC. This allows the snowboard to go around the turn without any skidding, since the snowboard is always pointed in the same direction as its velocity v.
The figure below illustrates a purely carved turn for a snowboard that is flat on the snow. Reverse camber occurs when the force of the snowboarder's feet on the snowboard causes the snowboard to bend in a shallow "U" shape, as shown below.
Snowboards can be manufactured with a camber which is opposite to that shown in the figure above. In other words, the ends of the snowboard touch the ground while the middle of the snowboard is elevated. This is done to control how much the snowboard flattens out when the weight of the snowboarder is applied to the board.
A flat snowboard distributes the weight of the snowboarder more evenly over the snow surface, which means the snowboard doesn't dig into the snow as much, and snow resistance is reduced. This is useful when snowboarding with no tilt on the board. Alternatively, if the snowboard is manufactured flat, then the middle of the snowboard would sink more than the ends when the snowboarder's weight is applied, and movement through the snow would be more difficult.
However, the amount that the middle of the snowboard bends when a given weight is applied depends on the stiffness of the snowboard, which can vary in different snowboards. This allows the snowboard to match the radius of the turn. This tells us that snowboards must largely be selected based on the snowboarder's weight, and how much reverse camber is desired, which depends on the type of snowboarding to be done.
The projection of the sidecut radius R SC onto the snow surface must be a circle in order for the inside edge of the tilted snowboard to make a purely carved turn. But since the projection of the sidecut radius onto the snow surface is an ellipse, a purely carved turn is not possible. In other words, the inside edge of the snowboard would not be able to follow the curve defined by the ellipse. There would be some skidding as a result of the snowboard pointing in a direction different from the direction of its velocity v.
Therefore, the snowboard needs to have a reverse camber such that the sidecut radius, when projected onto the snow surface, is a circle.
The reverse camber must be great enough to shorten the length of the semi-major axis so that it equals the length of the semi-minor axis, which gives us a circle or very close to it. This allows the inside edge of the snowboard to make a purely carved turn. This is the radius of the turn for pure carving to occur. In the next section we will take a closer look at carving and how it relates to sidecut edge penetration into the snow.
To understand this consider the following. This gap is greater for a smaller sidecut radius, and this gap is smaller for a larger sidecut radius. The maximum amount of reverse camber occurs when this gap is closed — in other words, when the sidecut edge presses into the snow.
So the larger the gap, the more reverse camber is possible, since the snowboard can bend more in the middle before the sidecut edge presses into the snow. A snowboard with a smaller sidecut radius and larger gap between sidecut edge and snow surface , can accommodate a greater amount of reverse camber, which means it can carve smaller radius turns. A snowboard with a larger sidecut radius and smaller gap between sidecut edge and snow surface , can accommodate a lesser amount of reverse camber, which means it is best suited for carving larger radius turns.
Given the complexity of all these inter-related factors, the ability of a snowboarder to make a purely carved turn comes down to his ability to recognize the terrain and make adjustments, based on the factors just mentioned. Clearly, carving adds substantial complexity to the physics of snowboarding. In the next section we will look at the forces acting on a snowboarder that is going around a purely carved turn. Force Balance For Snowboarder Going Around A Purely Carved Turn As explained in the previous section, making a purely carved turn is desirable for a snowboarder since it minimizes how much he slows down.
Thus, it is useful to analyze the forces acting on a snowboarder during such a turn. To begin the analysis, we must first define the orientation of the snowboarder on a slope of arbitrary inclination which is the most general case.
This is necessary because the force of gravity affecting the motion of the snowboarder changes depending on which direction he is going along the slope. The figure below shows a schematic defining the orientation of the snowboarder on the slope. Where: g is the acceleration due to gravity, which is 9. The equipotential line is the line of constant altitude, and is perpendicular to the direction of gravity R T is the radius of the turn v is the velocity of the snowboarder along the turn, pointing in the direction of the snowboard The coordinate system xy is oriented such that the y -axis is perpendicular to the surface of the slope, and the x -axis lies along the surface of the slope and is perpendicular to the velocity v of the snowboarder, at the instant shown.
Note, we are assuming that the surface of the slope is planar and that three-dimensional effects are negligible. This type of acceleration is called negative acceleration. Velocity is mostly measured in miles per hour or kilometers per hour, but can also be measured using any distance and time measurements.
With the high speeds that can be achieved, snowboa Balancing the snowboard and riding on the rail, momentum keeps pushing on both of them down the rail. You may also see more torque when you are on the top of the mountain or hill and you are teetering on the edge. Putting more mass on the front of the snowboard will cause the front of the snowboard to droop downhill, therefore causing you to take off down the mountain.
So next time you go snowboarding, keep in mind all the things that involve physics, but still have fun. Always remember the most important thing of all, safety first.
Sports Illustrated for Kids Books. Kirkpatrick, Larry D. Physics: A World View. Fourth Edition. Harcourt College Publishers: Orlando, Florida, Get Access. Satisfactory Essays. Personal Narrative: Skiing Experience. Read More. Avalanches Words 3 Pages. Living in Antarctica Words 1 Pages. Living in Antarctica. Better Essays. Physics of Avalanches Words 3 Pages. Physics of Avalanches. Physics of Skiing Words 3 Pages.
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