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A Level Maths Edexcel > Mechanics > Flashcards

Flashcards in Mechanics Deck (28)
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1

What is a vector?

A quantity which had both magnitude and direction

2

What is a scalar?

A scalar quantity had a magnitude only

3

State what is means by the following modelling assumption: Particle
And state what the term means

Dimensions of the object are negligible

1) Mass of the object is concentrated at a single point
2) Rotational forces and air resistance can be ignored

4

State what is means by the following modelling assumption: Rod
And state what the term means

All dimensions but one are negligible

1) Mass is concentrated along a line
2) No thickness
3) Rigid

5

State what is means by the following modelling assumption: Lamina
And state what the term means

Object with area but negligible thickness

1) Mass is distributed across a flat surface

6

State what is means by the following modelling assumption: Uniform body
And state what the term means

Mass is distributed evenly

1) Mass of the object is concentrated at a single point at the geometrical centre of the body (centre of mass)

7

State what is means by the following modelling assumption: Light object
And state what the term means

Mass of the object is small compared to other masses

1) Treat object as having 0 mass
2) Tension the same at both ends of a light string

8

State what is means by the following modelling assumption: Inextensible string
And state what the term means

A string that does not stretch under load

1) Acceleration is the dame in objects connected by a taut inextensible string

9

State what is means by the following modelling assumption: Smooth surface

1) Assume that there is no friction between the surface and any object on it

10

State what is means by the following modelling assumption: Rough surface
And state what the term means

If a surface is not smooth

1) Objects in contact with the surface experience a frictional force if they are moving or are acted on by a force

11

State what is means by the following modelling assumption: Wire
And state what the term means

Rigid thin length of metal

1) Treated as one dimensional

12

State what is means by the following modelling assumption: Smooth and light pulley

1) Pulley has no mass
2) Tension is the same on either side of the pulley

13

State what is means by the following modelling assumption: Bead
And state what the term means

Particle with a hole in it for threading on a wire or string

1) Moves freely along wire/string
2) Tension is the same on either side of the bead

14

State what is means by the following modelling assumption: Peg
And state what the term means

A support from which a body can be suspended or rested

1) Dimensionless and fixed
2) Can be rough or smooth as specified

15

State what is means by the following modelling assumption: Air resistance
And state what the term means

Resistance experienced as an object moves through air

1) Usually modelled as being negligible

16

State what is means by the following modelling assumption: Gravity
And state what the term means

Force of attraction between all objects

1) Assume that all objects with mass are attracted towards the Earth
2) Earth's gravity is uniform and acts vertically downwards
3) g is constant and is taken as 9.8 m/s²

17

Define velocity

Rate of change of displacement

18

Average velocity =

Displacement from starting point / Time taken

19

Average speed =

Total distance travelled / Time taken

20

Define acceleration

The rate of change of velocity

21

What is the constant acceleration equation with s, u, v and t in it?

s = ((u + v)/2)t

22

What is Newton's First Law of motion?

An object at rest will stay at rest and that an object moving with constant velocity will continue to move with constant velocity unless an unbalanced force acts on the object

23

What will a resultant force on an object cause?

Will cause the object to accelerate in the same direction as the resultant force

24

What is Newton's second law?

The force needed to accelerate a particle is equal to the product of the mass of the particle and the acceleration produced. F = ma

25

What is Newton's third law?

For every action there is an equal and opposite reaction

26

Describe the forces if a rigid body is on the point of tilting

The reaction at any other support (or the tension in any other wire/string) is zero

27

When is a particle/rigid body in static equilibrium?

If it is at rest and the resultant force acting on the particle is zero

28

Describe what is true for a body in static equilibrium:

1) The body is stationary
2) The resultant force is zero
3) The resultant moment is zero