Flashcards in AS Mechanics Deck (24)

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1

## gravity

### force of attraction between all objects

2

## inextensible string

### a string that does not stretch under load- acceleration is the same in objects connected by a inextensible string

3

## light object

### mass of the object is small compared to other masses, like a string or pulley (treat objects as having zero mass)

4

## smooth surface

### assume there is no friction between the surface and any object on it

5

## weight

### gravitational force that acts vertically downwards

6

## friction

### a force that opposes the motion between two rough surface

7

## normal reaction

### the force which acts perpendicular to a surface when an object is in contact with the surface

8

## tension

### the force acting on an object when it is being pulled along by a string

9

## air resistance

### opposes motion

10

## buoyancy

### the upward force on a body that allows it to float or rise

11

## vector

### a quantity with both magnitude and direction (positive or negative)

12

## scalar

### a quantity with magnitude only (only positive)

13

## velocity

### rate of change of displacement

14

## Displacement-time graphs

###
Gradient represents the velocity

Average velocity= displacement from starting point/ time taken

Average speed= total distance travelled/ time taken

15

## acceleration

### rate of change of velocity

16

## Velocity-time graphs

###
Gradient represents the acceleration

Area under graph represents the distance travelled

17

## SUVAT Equations

###
v= u + at

s= 1/2 (u + v)t

v^2= u^2 + 2as

s= ut + 1/2 at^2

s= vt - 1/2 at^2

18

## Force of gravity

### It causes all objects to accelerate towards the earth. If you ignore the effects of air resistance, the acceleration is constant. The acceleration does not depend on the mass of the object

19

## Acceleration due to gravity

### Modelled as g= 9.8 m/s^2

20

## Newton's first law of motion

### an object at rest and an object moving with constant velocity will continue in the same state unless acted upon by an unbalanced force

21

## resultant force

### causes the object to accelerate in the same direction as the resultant force

22

## Newton's second law of motion

### the force needed to accelerate a particle is equal to the product of the mass of the particle and the acceleration produced (F=ma)

23

## Connected particles

### When all parts of the system are moving in the same straight line, the whole system can be treated as a single particle

24