A2 Forces and Momentum Flashcards
State Newton’s three laws of motion.
1st Law: An object at rest or in motion will remain in that state unless acted upon by a force.
2nd Law: Force equals mass times acceleration (F = ma).
3rd Law: For every action, there is an equal and opposite reaction.
Solve translational equilibrium problems using Newton’s 1st Law.
In translational equilibrium, the sum of forces acting on an object is zero, meaning the object will not accelerate.
Identify force pairs using Newton’s 3rd Law.
For every action force, there is an equal and opposite reaction force (e.g., Earth pulling on a ball, and the ball pulling on Earth).
List and describe contact forces.
Normal force (perpendicular to surfaces), frictional force (resists sliding), elastic force (restores shape), viscous drag (resists motion in fluids), buoyant force (upward force in fluids).
List and describe field forces.
Gravitational force (attractive force between masses), electric force (between charges), magnetic force (between magnetic poles or currents).
Define linear momentum.
Momentum is the product of mass and velocity (p = mv) and is conserved unless acted upon by an external force.
Define impulse and its relationship with momentum.
Impulse is the change in momentum caused by a force applied over a time period (Impulse = Force × Time).
Derive Newton’s 2nd Law from the definition of momentum.
F = Δp/Δt (force equals the rate of change of momentum).
Solve problems involving momentum in collisions and explosions.
Use conservation of momentum for elastic/inelastic collisions and explosions (one-dimensional for SL, two-dimensional for HL).
What is the acceleration of an object in circular motion?
Even if the speed is constant, the object experiences centripetal acceleration directed towards the center of the circle.
Solve problems involving centripetal force, acceleration, period, and angular velocity.
Use formulas:
Centripetal force (F = mv²/r)
Centripetal acceleration (a = v²/r)
Period (T = 2πr/v)
Angular velocity (ω = Δθ/Δt)
