Form 4 Term 1 Physics Unit 17 Mechanics 2

Question 1

Acceleration

Answer 1

The rate of change in speed is measured in metres per second squared

Question 2

Deceleration

Answer 2

Slowing down or negative acceleration

Question 3

Displacement

Answer 3

Quantity describing the distance from from start of journey to end of journey in a straight line with a direction
Example 50km due north of starting point

Question 4

Force

Answer 4

Is a push or a pull

Unit of force is the NEWTON N

Question 5

Magnitude

Answer 5

The magnitude tells us the size of the vector

Question 6

Moment

Answer 6

A turning force around a pivot - clockwise or counterclockwise

Measure in Newton-metres Nm3 (force and distance)

Force multiplied by the perpendicular distance to a pivot

Question 7

Stationary

Answer 7

Not moving

Question 8

Velocity

Answer 8

The speed an object moves in a particular direction

Question 9

Gravity

Answer 9

The force of attraction between all objects
More mass in an object means the it exerts a larger force of gravity

More mass = exerts more force of gravity

Question 10

Inversely

Answer 10

Two variables are inversely related if one decreases when the other increases

Question 11

Mass

Answer 11

Mass is measured in kilograms KGS

mass of an object is a measure of unwillingness of an object to change its velocity (to accelerate)

Large rock = more mass = hard to make it move quickly / gain velocity

Question 12

Matter

Answer 12

Sub atomic particles

Question 13

Oppose

Answer 13

When one things works against something else to reduce of eliminate effect

Example: an opposing force to a PUSH is a PULL

Question 14

Frictional force

Answer 14

Force that resists one object moving through or over something

Example: air resistance on a car as it drives along (like when hold hand out car window)

Question 15

Kinetic energy

Answer 15

Energy which an object possesses by being in motion

Question 16

Resultant force

Answer 16

The single force that could replace all the other forces acting on an object

Calculated by adding all forces together.

If all forces are equal the resultant force is zero

Question 17

Surface area

Answer 17

The total area of an object

Question 18

Terminal velocity

Answer 18

The max speed of an object - reached when the forces moving on the object are balanced by its frictional forces.

At terminal velocity acceleration is zero (it can’t go any faster it’s at maximum)

Question 19

Pressure

Answer 19

The force per unit

Measured in Pascals PA

Question 20

What does pressure determine ?

Answer 20

The effect of a force on a surface

Measures in Pascals - Pa

Question 21

What happens to acceleration at terminal velocity

Answer 21

It is at zero - the object has reached its maximum Speed

Question 22

What unit is pressure measured in and what is the symbol

Answer 22

Pascal

Pa

Question 23

What unit is force measured in and what is the symbol

Answer 23

newtons

N

Question 24

What unit is area measured in and what is the symbol

Answer 24

Metres squares

m2

Question 25

What does pressure help to do ?

Answer 25

Helps to move blood around the body Allows organisms to breathe

Question 26

What does bigger surface area mean for pressure

Answer 26

Means less presssure when greater surface area Normal Shoes on snow have lots pressure so sink into snow Snowshoes have big surface area so they reduce the pressure you exert on the snow so you don’t sink

Question 27

what did robert boyle discover

Answer 27

that volume is inversely proportional to pressure (more pressure equals less volume) he trapped a bubble of an air in a J shaped tube which was caped at one end. poured mercury in and slowly increased the pressure and the air bible got smaller more pressure causes less volume eg squeeze balloon

Question 28

what is the pressure in the atmosphere at sea level

Answer 28

100,000 Pascals (Pa)

Question 29

what did greek scientist archemide discover

Answer 29

the physical law of buoyancy

Question 30

what is the Archimedes Can/Eureka can theory?

Answer 30

any object immersed in a fluid is acted upon by an upward, or buoyant, force equal to the weight of the fluid displaced by the object. When an object is dropped into water it will float because of the upward or buoyant force on it

Question 31

pressure and gases

Answer 31

the pressure is created by the molecules colliding - the faster they collide the pore pressure and they push outwards

Question 32

if you contain a gas in a confined spaced what happens to pressure

Answer 32

it increases as there are more collisions - a balloon expands outwards

Question 33

what is the difference between velocity and speed

Answer 33

velocity is speed in a direction

Question 34

what happens to atmospheric pressure as you go higher

Answer 34

in increases because as altitude increases - the number of air molecules decrees - the weight of the air decreases - less air above the surface

Question 35

what is the relationship between pressure and volume

Answer 35

more pressure means less volume eg squeeze a balloon

Question 36

what is density

Answer 36

how closely packed particles are in a solid liquid or gas

Question 37

how do you calculate density

Answer 37

mass divided by volume

Question 38

do heavier items have more or less density

Answer 38

more as the particles re more closely packed in the same volume

Question 39

what is the unit for density

Answer 39

kg/m3 or g/gm3

Question 40

is water or ice more dense ?

Answer 40

about the same as same number of particles the space it takes up. ice cube and water take same space. When turn water to steam it has less density as particles get further apart

Question 41

forces are usually

Answer 41

a push or pull

Question 42

force is measure in what unit

Answer 42

Newtons

Question 43

what is turning force and what unit is it measured it

Answer 43

a Moment - measure in Newton metres (force and distance)

Question 44

when you draw graphs to show speed/distance etc what 4 things must you include

Answer 44

units line or curve points labels

Question 45

on velocity time graph how would you find displacement

Answer 45

o the areas under the line

Question 46

Newtons main law of motion

Answer 46

every action has an equal and opposite reaction that means - forces act in pairs