CIE A Level Physics复习笔记4.2.1 Density
Density Density is the?mass per unit volume?of an object Objects made from low-density materials typically have a lower mass For example, a balloon is less dense than a small bar of lead despite oc...
CIE A Level Physics复习笔记4.1.4 Conditions for Equilibrium
Equilibrium A system is in equilibrium when all the forces are balanced. This means: There is?no?resultant force There is?no?resultant torque An object in equilibrium will therefore remain at rest,...
CIE A Level Physics复习笔记4.1.3 Turning Effects of Forces
Couples A couple is a?pair?of forces that acts to produce?rotation?only Unlike moments of a single force, the moment of a couple doesn’t depend on a pivot, only on the perpendicular distance betwee...
CIE A Level Physics复习笔记4.1.2 Moments
What is a Moment? A moment is the?turning effect of a force Moments occur when forces cause objects to?rotate?about some pivot The moment of a force is given by Moment (N m) = Force (N) × perpendic...
CIE A Level Physics复习笔记4.1.1 Centre of Gravity
Centre of Gravity The centre of gravity of an object is?the point at which the weight of the object may be considered to act For example, for a person standing upright, their centre of gravity is r...
CIE A Level Physics复习笔记3.2.2 Elastic & Inelastic Collisions
Elastic Collisions When two objects collide, they may spring apart retaining all of their kinetic energy. This is a perfect elastic collision An elastic collision is one where?kinetic energy is con...
CIE A Level Physics复习笔记3.2.1 Conservation of Momentum
The Principle of Conservation of Momentum The principle of conservation of momentum is: The total momentum of a system remains constant provided no external force acts on it For example if two obje...
CIE A Level Physics复习笔记3.1.7 Terminal Velocity
Terminal Velocity For a body in free fall, the only force acting is its weight and its acceleration?g?is only due to gravity. The drag force increases as the body accelerates This increase in veloc...
CIE A Level Physics复习笔记3.1.6 Drag Force & Air Resistance
Drag Forces Drag forces are forces acting the?opposite?direction to an object moving through a fluid (either gas or liquid) Examples of drag forces are?friction?and?air resistance A key component o...
