Momentum

Momentum

Momentum is equal to Mass x Velocity

There are two types of momentum when related to snowboarding: Linear and Angular

Linear

• Deals with objects moving in one particular direction

A common mistake when dealing with linear momentum is saying that a heavier rider will have more velocity or speed then a lighter rider.  The riders will be going the same speed if on the same slope, however the larger rider will carry a lot more momentum.  Momentum does not affect velocity, it is determined by velocity

A common mistake by beginner riders is to think that if he does not clear a jump and land on the sloped part it will be okay. This is not the case. A rider wants to carry the momentum he previously had by landing on a slope instead of a flat surface, which will absorb the momentum of the rider very abruptly  If a snowboarder lands on flat ground, the impact on them is much greater than if they would have landed on a sloped surface. When a person lands on a flat surface, all the momentum is converted to an impact that acts on the snowboarder, while when landing on sloped ramp the snowboarder keeps most of the momentum and only loses some to an impulse that acts on them. Here is a video of why you don’t want to land on a flat surface after a large jump:

Angular

• Angular momentum is momentum related to rotation, such as a 360, 540, etc.

Angular momentum is a vector quantity. The direction of the angular momentum depends on the direction of rotation, in other words angular velocity and angular momentum have the same direction. This can be seen in the following diagram, from Sparknotes.com.

Angular momentum affects snowboarders when they are trying to do tricks. There is an entire type of trick which involves simply seeing how many times the snowboarder can spin around in one jump.  In order to maximize the number of spins while in the air, A snowboarder will want to maximize his angular velocity, so that he will spin faster.The boarder must decrease his rotational mass in order to increase his angular velocity. This is precisely what he is doing when he tucks his arms in tight to his body as he spins. When a large amount of an object’s mass is very close to its center of mass, it has a low rotational mass. On the other hand, when the mass of an object is very spread out, it has a high rotational mass. All this means is that in order to land a 1260, a rider has to draw in his arms to his center of mass to spin faster. A great example of a snowboarder maximizing his Angular Velocity and momentum is seen here: 

One of the scariest and most exhilarating parts of snowboarding is big air jumps, but all these jumps have to be very precise or bad things can happen.  One a rider leaves the jump and soars into the air,  he knows if he took off correctly or not.  Once in the air rotating, it is impossible to reverse momentum, however it can be affected using angular velocity. By expanding your center of gravity, you are slowing your angular velocity, which can protect a snowboarder from a big crash and possible injury. 

For a great video on what not to do in a jump look down. Dont try this is home