1.8 express a force as a push or pull of one body on another
A force is a push or pull that one object exerts on another
3 things a force can do to an object:
 change its speed
 change is shape
 change its direction
1.9 identify various types of force (for example gravitational, electrostatic etc.)
various types of force:
 push/pull (contact force)
 tensionthe pull at both ends of a stretch spring, string or rope
 compression
 thrust/upthrust
 load
 effort
 *weight/gravitational
 *electrical/electrostatic
 *magnetic
*the last three forces are noncontact, they can act without touching an object
SS 1.10 distinguish between vector and scalar quantities
SS 1.11 appreciate the vector nature of a force
SS 1.12 add forces that act along a line
SS 1.10 distinguish between vector and scalar quantities
Scalars have magnitude (size), Vectors have both magnitude and direction.
Scalars

Vectors

Speed

Velocity

Distance

Displacement

Mass

Weight/tension/compression
à forces

Temperature

Thrust

Energy

Drag

Charge

Upthrust

Volume

Acceleration

Area

Field strength –
magnetic/electrical/gravitational

SS 1.11 appreciate the vector nature of a force
Forces have magnitude and direction, it is therefore a vector. For example, weight is a force with magnitude, and it acts downwards. It is a vector, and you would normally use an arrow pointing downwards with its magnitude ("xN" N being the unitNewtons) to represent it in a diagram.
SS 1.12 add forces that act along a line
The forces act along a line, meaning they are collinear. You can add the forces together like scalars. For instance if two forces are acting on a box, both pushing towards the right side, one with a force of 4N and the other with 6N, then 4N+6N=10N (resultant force). So a total of 10N is acting on the box, pushing it to the right.
However, if one of the forces was acting to the left with say, 2N and the other to the right with 7N, then the resultant is 5N to the right. The 2N to the left cancels out 2N from the right. You can think of the force acting to the left as a negative value, like the reverse direction, so 7N + (2N) = 5N. It's good to use diagrams to help you out.
1.13 understand that friction is a force that opposes motion
Friction is a force that always opposes motion between 2 surfaces in contact.
1.14 recall and use the relationship between unbalanced force, mass and acceleration:
force=mass x acceleration
F= m.a
1.15 recall and use the relationship between weight, mass and g:
weight= mass x g
W= m x g
g=gravitational field strength, this is the gravitational force exerted per unit mass at a point in the field, it is a vector quantity. unit= N/kg
on earth, we consider g as 10N/kg, or g = 9.8 m/s^{2 }but we use g = 10 m/s^{2 }this is how an object in the Earth's gravitational field would accelerate if it was free fallwithout friction (this doesn't happen in the real world).
( to explain how we get to this:
a= F/m = mg/m = g )
1.16 describe the forces acting on falling objects and explain why falling objects reach a terminal velocity
2 forces act on falling objects:
 Earth's gravityWeight (W): has direction (vector quantity), pulls object downwards towards the centre of the Earth
 air resistance/drag (D)upwards force, pushes object upwards
Air resistance increases with speed. When an object first starts falling, their weight is greater than air resistance. (W>D) Hence it falls faster, accelerating towards the ground. However, as it gains speed, the air resistance increases until it eventually equals the object's weight. (W=D) Acceleration then becomes zero (a=0) and the object will have reached terminal velocity.
1.17 describe the factors affecting vehicle stopping distance including speed, mass, road condition and reaction time
vehicle stopping distance= *( reaction time (a.k.a thinking time) x constant speed ) + breaking distance
vehicle stopping distance= thinking distance + braking distance
*d=s x t, so it becomes thinking distance
thinking distance: how far the car travels at constant speed before the driver reacts by applying the car brakes
braking distance: distance travelled by the car as it decelerates to a stop
 as speed increases, stopping distance increases
 as mass increases, force needed to stop car increases (F=ma)
 dry weather=more friction, rainy=less friction, as water acts as lubricant
 as reaction time increases, stopping distance increases (If driver was drunk, their reaction would be slower, so reaction time increases, hence stopping distance increases)
SS 1.18 recall and use the relationship between momentum, mass and velocity:
SS 1.19 use the ideas of momentum to explain safety features
SS 1.20 use the conservation of momentum to calculate the mass, velocity or momentum of objects
SS 1.21 use the relationship between force, change in momentum and time taken:
force= change in momentum/time taken
SS 1.22 understand Newton's third law
E.g. when an object is falling, not only is weight acting on it downwards, but there is also air resistance pushing it upwards  the forces act in opposite directions on the same object.
Or for instance, when a car is driving, the driving force pushes the car forwards, but there is also friction acting in the opposite direction, if the driving force wasn't bigger than friction, the car would be slowing down...
1.23 recall and use the relationship between moment of a force and its distance from the pivot
momentum = mass x velocity
p= m x v
SS 1.20 use the conservation of momentum to calculate the mass, velocity or momentum of objects
SS 1.21 use the relationship between force, change in momentum and time taken:
force= change in momentum/time taken
SS 1.22 understand Newton's third law
Newton's Third Law of Motion:
For every action, there is an equal and opposite reaction, and these forces act on mutually opposite bodies.
i.e. forces occur in pairs.
Fab = Fab
E.g. when an object is falling, not only is weight acting on it downwards, but there is also air resistance pushing it upwards  the forces act in opposite directions on the same object.
Or for instance, when a car is driving, the driving force pushes the car forwards, but there is also friction acting in the opposite direction, if the driving force wasn't bigger than friction, the car would be slowing down...
1.23 recall and use the relationship between moment of a force and its distance from the pivot
moment= force x perpendicular distance from the pivot
moment= F x d
1.24 recall that the weight of a body acts through its centre of gravity
SS 1.25 recall and use the principle of moments for a simple system of parallel forces acting in one plane
SS 1.26 understand that the upward forces on a light beam, supported at its ends, vary with the position of a heavy object placed on the beam
SS 1.25 recall and use the principle of moments for a simple system of parallel forces acting in one plane
SS 1.26 understand that the upward forces on a light beam, supported at its ends, vary with the position of a heavy object placed on the beam
1.27 describe how extension varies with applied force for helical springs, metal wires and rubber bands
they all obey Hooke's Law up to their elastic limit
thanks to a correction by an anonymous person (see comments), it apparently should be:
helical springs and metal wires do obey Hooke's Law, but rubber bands do NOT follow Hooke's Law and the extension is NOT directly proportional to the force causing it.
thanks to a correction by an anonymous person (see comments), it apparently should be:
helical springs and metal wires do obey Hooke's Law, but rubber bands do NOT follow Hooke's Law and the extension is NOT directly proportional to the force causing it.
(y)
1.28 recall that the initial linear region of a forceextension graph is associated with Hooke's Law
Hooke's Law: The extension is directly proportional to the stretching force.
Hooke's Law only applies to the straight part of the graphinitial linear region, up to the limit of proportionality.
Elastic limitif a spring is taken beyond this limit, it won't return to its old shape=deformed.
1.29 associate elastic behaviour with the ability of a material to recover its original shape after the forces causing deformation have been removed
Deformation from the limit of proportionality to the Elastic limit is still reversible; but
Beyond the elastic limit, deformation is irreversible=permanent deformation or plastic deformation.