7 - Definitions Flashcards
Newtons 1st Law
Object will remain at rest or have uniform motion (no acceleration) in a straight line unless there’s external net force.
Newtons 3rd law
Forces have an equal and opposite reaction force:
E.g objects weight pulling towards earth 🌏
Earth is pulling towards the object with the same force.
Newton’s 2nd Law
The net (resultant) force acting on an object is directly proportional to the rate of change of its momentum and is in the same direction.
Forces are not balanced, acceleration depends on net force actin and mass.
Acceleration depends directly on net force acting and inversely on mass.
All interactions can be explained in terms of 4 fundamental forces:
Gravitational
Electromagnetic
Strong Nuclear
Weak Nuclear
E.g. Of electromagnetic force
Walking exerts a backwards force on the ground and it exerts a forwards force on you
Momentum =
Mass x velocity
When two (or more) objects collide or interact they transfer both momentum and
K.E
The group of objects interacting is referred to as a ______ system
Closed
The principle of conservation of momentum
The total momentum in a specific system remains constant, with no external forces acting on it.
Zero momentum
Gun recoil = total system momentum = 0
Perfectly Elastic collision
Momentum, total energy and K.E = all conserved
Inelastic collision
Momentum and total energy =conserved
K.E = not conserved (wasted on heat etc.)
F (net force) is proportional to
🔼t
Force x time
Change in momentum
Change in momentum is equal to the _______ of the force
Impulse
Ns
