Unit 2 Flashcards Preview

Nat 5 Physics > Unit 2 > Flashcards

Flashcards in Unit 2 Deck (48):
1

What is a vector quantity?

Has magnitude and direction

2

Give an example of a scalor quantity

Distance, speed, time, power, etc.

3

Give an example of a vector quantity

Displacement, velocity, acceleration, force

4

What is displacement?

The direct distance from start to end

5

What is speed?

The distance traveled per unit time

6

What is velocity?

The displacement per unit time

7

To find a resultant force what would be used?

Pythagoras and trigonometry

8

Vectors can be combined to produce what?

A resultant vector

9

What is acceleration?

The change in velocity per unit time

10

What causes an object to accelerate when dropped?

An unbalanced force

11

Ignoring friction do all objects in free fall accelerate at the same rate?

Yes

12

On a velocity time graph, how is displacement calculated?

Area of each shape is found then added together

13

What is the unit of force and how can it be measured?

Newtons (N), using a Newton balance

14

When does a balanced force occur?

When an object has equal sized forces acting in opposite direction

15

What happens to the motion of an object when the forces are balanced?

Will be at rest or traveling in a straight line at a constant velocity

16

What happens to the motion of an object when the forces are unbalanced?

Object will be accelerating or decelerating

17

An object falling at terminal velocity will have what kind of forces acting on it?

Balanced forces. Weight down will balance with air resistance upwards

18

When does an unbalanced force occur?

When an object has forces acting on it that do not cancel each other out

19

When does friction occur?

When two surfaces are in contact while moving past each other

20

What is a scalor quantity?

Quality that only has magnitude

21

How can friction be reduced?

If the surface contact area is reduced or surface is smoother

22

When friction acts between surfaces what types of energy are there?

Kinetic energy is transformed into heat energy

23

What is Newton's first law?

An object will remain at rest or remain at a constant velocity unless acted on by an unbalanced force

24

What is Newton's second law?

The acceleration of an object is directly proportional to the unbalanced force and inversely proportional to the mass of an object

25

What is Newton's third law?

If object A exerts a force on object B, then object A exerts an equal but opposite force on object A

26

What is mass?

The amount of matter in an object

27

What is weight?

The force on an object caused by the force of gravity

28

What is work done?

An amount of energy being transferred

29

When is a object a projectile?

If it has both vertical and horizontal motion

30

What happens to the vertical and horizontal motion in a projectile?

Horizontal velocity is constant. Vertical velocity is increasing

31

As the height (altitude) of a satellite increases, what happens to the period?

It increases

32

What are some uses of satellites?

Telecommunications, weather forecasting, satnav

33

How does a rocket take off in terms of forces and motion?

If the up thrust force remains constant, the unbalanced force increases and acceleration increases

34

When a space craft re enters Earth's atmosphere, what does friction cause?

It transforms kinetic energy into heat energy

35

If the angle of re-entry is too steep what happens to the spacecraft?

Drag force is too large, too much heat and space craft is destroyed

36

If the angle of re-entry is too shallow what happens to the spacecraft?

Drag force is too small, spacecraft returns to orbit

37

What is used to protect spacecrafts during re entry?

Silica tiles?

38

Why are silica tiles used to protect spacecrafts?

They have a high melting point, good insulators, will remain a constant temperature as they melt. Painted black to radiate heat

39

What is specific latent heat?

The heat energy needed to change the state of 1kg of material

40

What is specific latent heat of vaporisation used for?

The change between liquid and gas

41

What is specific latent heat of fusion used for?

The change between a liquid and a solid

42

What type of energy is either absorbed or released when a material changes state?

Heat energy

43

What can be used to identify elements present within stars?

Spectra

44

Where does a continuos spectrum come from?

A hot white light source

45

Where does a line spectrum come from?

A hot gaseous element. Shows frequencies on a black background

46

What is a light year?

The distance light travels in one year

47

What is one light year?

9.47 x 10^15 m

48

What does a continuous spectrum contain?

All the wavelengths (colours) of light