Momentum–depth relationship in a rectangular channel Momentum–depth relationship in a rectangular channel In classical physics, momentum is the product of mass and velocity and is a vector quantity, but in fluid mechanics it is treated as a longitudinal quantity (i.e. one dimension) evaluated in the direction of flow. Additionally, it is evaluated as momentum per unit time, corresponding to the product of mass flow rate and velocity, and therefore it has units of force. The momentum forces considered in open channel flow are dynamic force – dependent of depth and flow rate – and static force – dependent of depth – both affected by gravity. The
Wheelie to mass times acceleration, then the minimum power required for a wheelie can be expressed as the product of mass, velocity, and the minimum acceleration required for a wheelie: Thus the minimum power required is directly proportional to the mass of the vehicle and to its velocity. The slower a vehicle is moving, the less power is required to perform a wheelie, and that is without even considering the power required to overcome air drag, which increases with the cube of velocity. Therefore, the least amount of power required is when the vehicle begins accelerating from rest. In the case