Section 1 Flashcards
(85 cards)
1
Q
What’s current base unit
A
A
2
Q
What’s temperatures base SI unit
A
K
3
Q
What’s the base unit for amount of a substance
A
Mol
4
Q
What’s the derived unit for frequency
A
Herts
Hz
5
Q
What’s the derived unit for force
A
Newton
N
6
Q
What’s the derived unit for energy
A
Joule J
7
Q
What’s the derived unit for power
A
Watt
W
8
Q
What’s the derived unit for pressure
A
Pascal
Pa
9
Q
What’s the derived unit for electric charge
A
Coulomb C
10
Q
What’s the derived unit for electric potential difference
A
Volt
V
11
Q
What’s the derived unit for electric resistance
A
Ohm
12
Q
What’s the derived unit for magnetic flux density
A
Tesla T
13
Q
Giga
A
10 power 9
14
Q
Mega
A
10 power 6
15
Q
Kilo
A
10 power 3
16
Q
Centi
A
10 power -2
17
Q
Milli
A
10 power -3
18
Q
Micro
A
10 power -6
19
Q
Nano
A
10 power -9
20
Q
Scalar is
A
Has a size or a magnitude
21
Q
Vector has
A
A size or magnitude and a specific direction
22
Q
Recall some scalar quantities
A
Mass Speed Distance Energy TenperAture
23
Q
Recall some vector quantities
A
Force or weight Velocity Displacement Acceleration Momentum
24
Q
What is velocity?
A
A speed in a stated direction
25
What’s the equation for average speed?
Total distance travelled\total time taken
S=D/T
D=S x T
M/s. M. S
26
What’s on the axis on distance/time graphs
Distance on y
| Time on x
27
What does the gradient of a distance/time graph tell you
About the motion of the vehicle
28
If the gradient is a diagonal line what does it tell us
It’s a constant or steady speed
29
If the line is curving up wards
It’s accelerating
30
If line goes up then starts to curve slowly down
Deceleration
31
If like is a horizontal line
Stationary vehicle
32
What’s the equation for acceleration
= change in velocity
| —
33
Equation including velocity
(Final velocity)^2 - (initial velocity)^2 = 2 x acceleration x distance
V^2 - u^2 = 2 x a x X
V^2 = u^2 + 2ax
34
What do velocity/time graphs show
How the velocity of a vehicle changes with time
35
What can you work out with a velocity/time graph
The acceleration and distance travelled
36
What’s on each axis on a velocity/time graph
Velocity on y axis
| Time on x axis
37
What does the slope or gradient of a velocity/time graph tell you
The acceleration of the vehicle
38
How do you work out the distance travelled in a velocity/time graph
Area under the graph
39
Difference in distance/time graphs and velocity/time graphs
Gradient of d/t tells constant/steady speed
Gradient v/t tells acceleration
Horizontal line on d/t tells you student is stationary
Horizontal line on v/t tells u constant velocity
40
What equipment can speed be determined with
Light gates connected to a computer or a data logger
41
Describe light gate method
There a vehicle with a card on it
Vehicle is released from it’s starting position and it moves down the slope
Light gate is attached to laptop
The light beam is cut by the card as it enters the light gate and the timer starts
The beam remains cut until the back of the card passes out of the light gate
When the card leaves the light gate the light beam stops the timer
The speed is found from the length of card\time
42
How can you measure the speed of falling objects
Using light gates
Acceleration due to gravity is
10m/s^2
This means that falling objects will increase its speed by 10 every second when falling in a sense of frictional or resistive forces
However for a piece of falling paper this terminal velocity value will decrease considerably of resistive forces
43
Speed for walking
1.5 m/s
44
Speed of running
3 m/s
45
Speed of cycling
6 m/s
46
Speed of driving
13 m/s
47
Speed of sound in air
330 m/s
48
Speed of airliner
250 m/s
49
Speed of commuter train
55 m/s
50
Speed of gale-force wind
16 m/s
51
What’s Newton’s first law?
A body will remain at rest or continue in a straight line at a constant speed as long as the forces acting on it are balanced
52
According to Newton’s first law what happens when the resultant force on a body is 0?
Body is moving at a constant velocity or it is at rest
53
According to Newton’s first law when happens the the body where the resultant force is not 0
The speed and/or the direction of the body changes
54
Recall Newton’s second law
When a resultant force Acts on a mass then there will be a change in its velocity.
The resultant force determines the size and direction of the subsequent acceleration of the mass
55
Recall Newton’s second law formula
Force = mass X acceleration
F = ma
56
Formula for acceleration
Force/ mass
57
Acceleration is in the same direction as the
Force
58
When the resultant force is zero what else is zero
Acceleration
59
What’s a negative force
The object is accelerating backwards or is slowing down
60
What’s inertial mass
A measure of how difficult it is to change the velocity of a moving object and is defined as the ratio ‘force over acceleration’
61
What is weight?
The force that a body experiences due to its mass and the size of the gravitational field that it is in
62
What quantity is weight?
| What’s it measured in
Vector
| Newton’s
63
Equation for weight
Weight=mass x gravitational field strength
W = m x g
64
What is the weight of an object directly proportional too?
The value of g, do a mass will weigh more on earth than it does on the moon
65
How is weight measured?
With a newtonmeter
66
What’s mass
A measure of the amount of matter that is contained within a three-dimensional space
67
What quantity is mass
| What’s it measured in
A scalar
Kilograms
68
What does gravitational field strength depend on
The mass of the body
| The radius of the body
69
When will a body have a large gravitational field strength
Large mass
| Small radius
70
Gravitational field strength on earth
10 N/kg
71
Gravitational field strength on moon
1.6 N/Kg
72
Gravitational field strength on Jupiter
26 N/kg
73
Gravitational field strength on Neptune
13.3 N/kg
74
Gravitational field strength on mercury
3.6 N/kg
75
Gravitational field strength on mars
3.75 N/kg
76
Gravitational field strength on neutron star
10^12 N/kg
77
What’s the aim in the core practical investigating force and acceleration
To investigate the effect of mass on the acceleration of a trolley
78
What’s the apparatus in investigating force and acceleration of a trolley
```
Trolley
Light gates
Data logger
Card of known length
Slope or ramp
Masses
```
79
Why can an accelerating mass greater than 100 g be dangerous in investigating force an acceleration
May hurt someone if it hits them at speed so must bear in mind when designing investigations
80
Why is it better to use light gates and other electronic equipment to record values than using a ruler and stopwatch
Because it’s way more accurate
81
What’s the method for investigating forces and acceleration
Set up apparatus as shown
Set up light gates to take velocity and time readings for you
Record velocity and time for different values of mass on trolley
Work our acceleration by dividing difference velocity by time for card to pass between both gates
If changin mass the slope and gradient need to remain the same
82
Conclusion of investigating force and acceleration
The acceleration of trolley does not depend on mass of trolley and will remain fairly constant throughout
83
Kept points to remember about core practical investigating force and acceleration
Acceleration is change in speed/time
Two velocity’s needed
Time difference between readings
Velocity is rate of change of displacement and acceleration is the rate of change of Velocity
Rate means ‘per unit time’
V=changeX / changeT
84
What core practical involves force and acceleration
Trolley
85
What do the symbols v u a x t stand for
A acceleration
T time
X distance
U initial velocity
