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Key Equations

PhysicsKey Equations

8.1 Linear Momentum, Force, and Impulse

impulse	$F_{net} Δ t$
impulse–momentum theorem	$Δ p = F_{net} Δ t$
linear momentum	$p = m v$
Newton’s second law in terms of momentum	$F_{net} = \frac{Δ p}{Δ t}$

8.2 Conservation of Momentum

law of conservation of momentum	p_tot = constant, or p_tot = p′_tot
conservation of momentum for two objects	p₁ + p₂ = constant, or p₁ + p₂ = p′₁ + p′₂
angular momentum	L = I $ω$

8.3 Elastic and Inelastic Collisions

conservation of momentum in any collision, including elastic collisionselastic collision	$m_{1} v_{1} + m_{2} v_{2} = m_{1} {v^{'}}_{1} + m_{2} {v^{'}}_{2},$
conservation of momentum in a perfectly inelastic collision	$m_{1} v_{1} + m_{2} v_{2} = (m_{1} + m_{2}) v^{'}$
conservation of momentum along x-axis for 2D collisions	$m_{1} v_{1} = m_{1} {v^{'}}_{1} \cos θ_{1} + m_{2} {v^{'}}_{2} \cos θ_{2}$
conservation of momentum along y-axis for 2D collisions	$0 = m_{1} v^{'}_{1} \sin θ_{1} + m_{2} v^{'}_{2} \sin θ_{2}$

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- Book title: Physics
- Publication date: Mar 26, 2020
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- Book URL: https://openstax.org/books/physics/pages/1-introduction
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