Flashcards in Forces and motion Deck (33):

1

## Acceleration

### rate of change of velocity

2

## Braking distance of a car

### The distance travelled by the car after the brakes are applied until the car stops

3

## Braking force

### the frictional force applied by the road on the tyre (in the opposite direction to the motion of the vehicle, that brings the vehicle to rest)

4

## Brittle

### Has no plastic region — breaks at its elastic limit

5

## Centre of Gravity

### The point on the object where the total weight (appears) to act

6

## Conditions for Mechanical Equilibrium

### Resultant force = 0, Resultant torque = 0

7

## Couple

### Two equal but opposite forces acting along different lines

8

## Density

### Density = Mass/Volume

9

## Displacement

### A vector directed from initial position to final position having magnitude equal to the distance between those points

10

## Ductile

### Large plastic region - can be drawn into a wire

11

## Elastic Limit

### When exceeded, a permanent deformation will remain when the stress is removed

12

## Hooke's Law

### Extension is proportional to the force applied up to the limit of proportionality

13

## Joule

### When a force of 1N acts over a distance 1m in the direction of the force, then the work done is equal to 1 joule

14

## Moment of a force

### Moment = force x perpendicular distance from pivot

15

## Newton

### The force required to cause a mass of 1kg to have an acceleration of 1m/s^2

16

## Plastic Deformation

### The material does not return to its original length when the stress is removed

17

## Power

### Rate of work done

18

## Pressure

### Pressure = Force / Area

19

## Principle of conservation of energy

### Energy cannot be created or destroyed; it can only be transformed. Hence, the total energy of a system remains constant

20

## Principle of moments

### The sum of the clockwise moments must equal the sum of the anti-clockwise moments about any point in equilibrium

21

## Resultant force

### The vector sum of all the individual forces acting on a body

22

## Stiff

### A stiff material has a high/large Young Modulus

23

## Stopping distance of a car

### Thinking distance + Braking distance

24

## Tensile Strain

### Extension per unit original length

25

## Tensile Stress

### Tensile force per unit cross-sectional area perpendicular to the force

26

## Strong

### Can take a high (maximum) stress before breaking

27

## Torque of a couple

### One of forces x perpendicular distance between the forces

28

## Thinking distance

### The distance travelled by the car in the time taken by the driver to react

29

## Vector quantity

### A quantity with magnitude and direction

30

## Velocity

### Rate of change of displacement

31

## Watt

### the power used when 1 joule of work is done per second

32

## Work done by a force

### Force x distance moved in the direction of the force

33