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Flashcards in 2a Deck (45)
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1

Difference between Speed and Velocity

Speed is how fast your going with no regard for direction. Velocity however must also have the direction specified.

2

Distance-Time Graph equation

Speed= Distance x Time

3

Formula for Acceleration

Change in velocity / Time taken

4

Velocity-Time Graph, how to find Acceleration

Acceleration= gradient= vertical change/ horizontal change

5

Difference between Weight and Mass

Mass is just the amount of stuff, weight is caused by the pull of the gravitational force.

6

What is Mass measured in?

Kg

7

What is Weight measured in?

Newtons

8

Formula relating Mass, Weight and Gravity?

Weight= mass x gravitational field strength

9

Define resultant force

Overall force on a point or an object

10

How do you work out Resultant Force?

F=ma m=mass (kg) a=acceleration in metres per second squared F=the resultant force in Newtons (N)

11

What is Terminal Velocity?

When falling objects first set off, the force of gravity is much more than the frictional force slowing them down, so they accelerate. As the speed increases the friction builds up. This gradually reduces the acceleration until eventually the frictional force is equal to the accelerating force and then it won't accelerate anymore. It will have reached its maximum speed or terminal velocity and will fall at a steady speed.

12

What two factors affect your stopping distance?

Thinking Distance and Braking Distance

13

What two things affect your Thinking Distance?

How fast your going, how dopey you are

14

What four things affect your Braking Distance?

How fast your going, how good your brakes are, how good the tyres are, how good the grip is

15

What is the formula for Work Done?

Work Done= Force x Distance

16

How do you work out somethings Gravitational Potential Energy?

= mass x g x height
(g= gravitational field strength)

17

How do you work out somethings Kinetic Energy?

= 1/2 x mass x speed squared

18

To stop a moving car, the energy is converted to...

heat energy as friction between the wheels and the brake pads, causing the temperature of the brakes to increase

19

Extension of an Elastic Object is Directly Proportional to Force, the equation is...

Force= k (the spring constant, N/m) x e (extension, m)

20

What is the limit of proportionality in springs?

The maximum force that the elastic object can take and still extend proportionally

21

What is the equation for Power?

Power= Work Done (or energy transferred) / Time taken

22

What is power measured in?

Watts or J/s

23

Equation for Momentum

Momentum (kgm/s) = Mass (kg) x Velocity (m/s)

24

Name five ways cars are designed to increase safety

Brakes, crumple zones, side impact bars, seat belts and air bags

25

What is the build-up of static caused by?

Friction

26

Explain Static Electricity

When certain insulating materials are rubbed together, negatively charged electrons will be scraped off one and dumped on the other. This will leave a positive static charge on one and a negative static charge on the other. Which way the electrons are transferred depends on the two materials involved. Electrically charged objects attract small objects placed near them.

27

Two things with opposite electric charges are...

Attracted

28

Two things with the same electric charges will...

Repel each other

29

An example of a good conductor

Metal

30

What is Current?

The flow of electric charge round the circuit. Current will only flow through a component if there is potential difference across that component. Unit= amperes (A)