Forces

Question 1

What are Scalar Measurements

Answer 1

Measurements with only magnitude

Question 2

What are Vector measurements

Answer 2

Measurements with magnitude and direction

Question 3

Examples of Scalar Measurements

Answer 3

Speed, Distance, mass, temp. and time

Question 4

Examples of Vector Measurements

Answer 4

Force,Velocity ,Displacement,acceleration and momentum

Question 5

What is the equation that links speed,distance and time

Answer 5

Speed = Distance/time

Question 6

What is the equation that links acceleration,change in distance and time

Answer 6

Acceleration = Change in distance/time

Question 7

Define acceleration

Answer 7

Quantity that tells us how quickly an objects velocity is changing

Question 8

Define Deceleration/Retardation

Answer 8

How quickly an objects velocity is decreasing

Question 9

What does the gradient of a Distance/Time graph tell us

Answer 9

Tell us how fast the object is travelling and no gradient means it is stationary

Question 10

What does the gradient of a Velocity/Time graph tell us

Answer 10

• Line going up shows acceleration
• Line going down shows retardation
• Flat gradient shows constant speed/stationary so 0 acceleration

Question 11

How do you work out the acceleration from a velocity/time graph

Answer 11

You work out the gradient

Question 12

How do you work out the distance travelled from a Velocity/Time graph

Answer 12

You work out the area of the graph

Question 13

What is the equation that links weight,mass and gravitational field strength

Answer 13

Weight = mass * gravitational field strength

Question 14

What is gravitational field strength (unless told explicitly to use another value)

Answer 14

g = 9.8 N/kg

Question 15

How are forces represented in diagram

Answer 15

Forces are represented by arrows. The size of the arrow represents magnitude while direction shows direction of the force

Question 16

What is the difference between mass and weight

Answer 16

Mass is substance measured in kg

Weight is the force objects experience due to gravity

Question 17

How do you work out the resultant force

Answer 17

1) Add forces together
2) if resultant force is 0 the object will stay moving in that direction at constant speed
3) if resultant force is more than 0 it will accelerate in that direction

Question 18

What is the equation for Pythagoras

Answer 18

a^2 + b^2 = c^2

Question 19

What is terminal velocity

Answer 19

When an object falls and the 2 forces balance out over time

Question 20

How do you work out diagrams when there is no angle involved

Answer 20

1) choose an appropriate scale
2) Draw a scaled diagram using ruler and protractor
3) to work out magnitude measure length of diagonal line and multiply length by scale

Question 21

How do you work out diagrams when 2 components are perpendicular to each other

Answer 21

look at notes for example

Question 22

What is Newtons 1st law

Answer 22

a stationary object stays stationary

a moving object continues to move at the same velocity unless enacted upon by an external force

Question 23

What is Newtons 2nd law

Answer 23

Force= Mass*Acceleration

Question 24

What is Newtons 3rd law

Answer 24

For every action there is an opposite and equal reaction this is why we don’t fall through a chair when we sit on it.

Question 25

Define a contact force

Answer 25

-When 2 objects have to be touching for a force to act

Question 26

Define a non-contact force

Answer 26

-When 2 objects don't have to be touching

Question 27

What is the equation that links force,spring constant and extension

Answer 27

Force= spring constant*extension

Question 28

What are the units for spring constant

Answer 28

N/m

Question 29

What are the units for acceleration

Answer 29

m/s/s or m/s^2

Question 30

What is the equation that links kinetic energy,mass and velocity

Answer 30

KE = 0.5*Mass*Velocity^2

Question 31

What is the equation that links Gravity potential energy,mass,gravitational field strength and change in height

Answer 31

GPE= mass*g *change in height

Question 32

What is the equation for efficiency

Answer 32

Useful Energy Efficiency = --------------------- * 100 Total Energy

Question 33

Define Efficiency

Answer 33

How much energy we supply that is turned into useful energy

Question 34

What is the equation that links Power,energy and time

Answer 34

Power(watts)= energy (j) / (time (s)

Question 35

What is the equation that links work done,force and distance

Answer 35

• Work Done = Force*Distance

Question 36

What is the equation that links momentum,mass and velocity

Answer 36

• Momentum (kgm/s) = mass * velocity

Question 37

What is the unit for momentum

Answer 37

(kgm/s)

Question 38

What is the Law of conservation of momentum

Answer 38

• When 2 or more objects collide, the total momentum conserved before and after is the same, so you add the momentum

Question 39

What is the equation that links moment,force applied * distance to pivot

Answer 39

Moment= Force applied * distance to pivot (clockwise or anti)

Question 40

What is the equation for stopping distance

Answer 40

Stopping distance = braking distance + thinking distance

Question 41

Define centre of mass

Answer 41

the weight of an object can be considered to act at a single point

Question 42

How do levers help use less force

Answer 42

• Levers increase the distance from the pivot from the pivot, this means less force is required to get the same moment

Question 43

How do larger and smaller gears interact

Answer 43

* If a larger gear is driven by a smaller gear, the large gear will rotate slowly but will have a greater moment * If a smaller gear is driven by a larger gear, the larger gear will rotate quickly but will have a smaller moment

Question 44

Define pressure

Answer 44

how much force is acting on a given area. It is measured in a unit called pascals or Nm2

Question 45

how does atmospheric pressure work

Answer 45

the pressure decreases as you go up and increases as you go down

Question 46

How do our bodies deal with pressure

Answer 46

When pressure acts on a body, it has the same outward pressure from our body, so we aren’t squished.

Question 47

What happens to out bodies as you go higher

Answer 47

When people go up and the atmospheric pressure decreases the pressure in our bodies is greater than the outward it causes internal damage and sickness.

Question 48

What is the equation for pressure in liquids

Answer 48

• pressure = height of column (m) × density of the liquid × gravitational field strength

Question 49

What is the equation for density

Answer 49

density= mass/volume

Question 50

What is the equation for pressure

Answer 50

Pressure (Pascals) = force/area

Question 51

What is the speed of sound

Answer 51

330m/s

Question 52

How does weight and upthrust interact

Answer 52

When weight = upthrust an object floats, measured by the amount of water an object displaces. The size of the upthrust depends on the size of the object i.e. going into a bath

Question 53

What do sankey diagrams show

Answer 53

the amount of chemical energy input turns into useful and wasteful energy