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The impulse delivered by a varying force is the integral of the force F with respect to time: =. The SI unit of impulse is the newton second (N⋅s), and the dimensionally equivalent unit of momentum is the kilogram metre per second (kg⋅m/s).
The time derivative of the momentum is =, which, upon identifying the negative derivative of the potential with the force, is just Newton's second law once again. [ 60 ] [ 9 ] : 742 As in the Lagrangian formulation, in Hamiltonian mechanics the conservation of momentum can be derived using Noether's theorem, making Newton's third law an idea ...
and the cross-product is a pseudovector i.e. if r and p are reversed in direction (negative), L is not. In general I is an order-2 tensor, see above for its components. The dot · indicates tensor contraction. Force and Newton's 2nd law: Resultant force acts on a system at the center of mass, equal to the rate of change of momentum:
If the net force experienced by a particle changes as a function of time, F(t), the change in momentum (or impulse J) between times t 1 and t 2 is = = (). Impulse is measured in the derived units of the newton second (1 N⋅s = 1 kg⋅m/s) or dyne second (1 dyne⋅s = 1 g⋅cm/s)
The force in the equation is not the force the object exerts. Replacing momentum by mass times velocity, the law is also written more famously as = since m is a constant in Newtonian mechanics. Newton's second law applies to point-like particles, and to all points in a rigid body.
The angular momentum equation can be used to relate the moment of the resultant force on a body about an axis (sometimes called torque), and the rate of rotation about that axis. Torque and angular momentum are related according to =, just as F = dp/dt in linear dynamics. In the absence of an external torque, the angular momentum of a body ...
Traditionally the Newton–Euler equations is the grouping together of Euler's two laws of motion for a rigid body into a single equation with 6 components, using column vectors and matrices. These laws relate the motion of the center of gravity of a rigid body with the sum of forces and torques (or synonymously moments) acting on the rigid body.
Internal forces between the particles that make up a body do not contribute to changing the momentum of the body as there is an equal and opposite force resulting in no net effect. [3] The linear momentum of a rigid body is the product of the mass of the body and the velocity of its center of mass v cm. [1] [4] [5]