Key Points: 4. Mechanics and Materials: Paper 1: Physics A Level AQA

Resolving a vector means ____________.

Splitting it up into its horizontal and vertical components.

Where an object is in equilibrium, the moments on it about a point are __________.

Balanced

Couple

A couple is a pair of equal and opposite parallel forces acting on the same body that do not act in the same line.

Centre of Mass

The centre of mass is where the mass of an object can be considered to be concentrated.

Newton’s Laws of Motion

Newton’s first law: ‘The velocity of an object will not change unless a resultant force acts upon it’.

Newton’s second law: f = ma (force in N equals mass in kg times the acceleration in ms^-2).

Newton’s third law: ‘Every force has an equal and opposite force’.

What is SUVAT stand for?

S = Displacement

U = Initial velocity

V = Final velocity

A = Acceleration

T = Time

Friction

Friction is a force that opposes motion when moving on a solid.

Drag

Drag is a force that opposes motion in a fluid. It usually increases with speed.

Lift

Lift is an upward force created on an object as it moves through a fluid due to the shape of an object.

Terminal Velocity

Terminal Velocity happens when frictional forces equal the driving force, causing equilibrium and zero acceleration.

Impulse

Impulse is the change in momentum or the product of force and time.

Density

Density is the mass of a material per unit volume.

Limit of Proportionality

The limit of proportionality is the point beyond which Hooke’s law no longer applies.

Elastic Limit

The elastic limit is the maximum stress that can be applied without permanent/plastic deformation which is when it does not return to its original shape.

Tensile Stress

Tensile Stress is the force applied per unit cross-sectional area, measured in Pa or Nm^-2.

Tensile Strain

Tensile Strain is the extension per unit original length and has no unit.