P5-forces Flashcards
what is scaler
only has magnitude( size)
examples of scaler
mass
temperature
speed
time
distance
energy
what is vector
both magnitude and direct
examples of vector
force
velocity
acceleration
displacement
weight
what is a force
A force is a push or a pull that acts on an object due to interaction with another object and are measured in Newtons.
what are two types of forces with examples?
contact forces
non contact force
what is a contact force?
examples of contact force
2 objects that are physically touching for the force to occur. eg. friction/air resistance
what is a non contact force?
examples of a non contact force
2 objects that dont need to physically be touching for the force to occur
eg. magnetic force, gravitation potential force
what is mass?
how much matter the object has in it (Scaler)
mass does not depend on where the object is
what is weight?
the force acting on an object due to gravity.
weight does depend on where the object is
describe the relationship between the mass and weight of an object
the mass of an object is directly proportional to the weight of an object
how do we measure weight?
using a newton meter
what is the centre of mass
The weight of an object (the force due to gravity) can
be considered to act a single point.
what is a resultant force
a single force that has the same
effect as all of the original forces acting together.
To work it out you do larger force minus smaller force
what is work done
the amount of force needed to move an object a certain distance
what is elastic deformation
Once the forces are removed, then it returns to its original
shape and length.
what is inelastic deformation
Once the forces are removed, then the material does not
return to its original shape and length.
what is distance
How far an object moves.
as it doesnt involve direction it is scaler.
what is displacement
the distance an object moves in a straight line from the start
point to the finish point and the direction of that straight line.
what is speed
how fast you are going with no regard to the direction.
what is velocity
the direction and the speed
what are the typical speeds
normal walking speed-1.5m/s
running speed- 3m/s
cycling speed 6m/s
what factors can speed depend on
fitness- the younger the fitter a person the quicker they will be
terrain- smoother ground is better compared to hills
distance travelled- if you run a long distance you start off faster
more speeds you may be asked about
car on main road- 13m/s
fast train in uk- 50m/s
cruising aeroplane 250m/s
speed of sound in air 330m/s
important things to know for acceleration 1/2 graphs
The gradient = acceleration
Flat section represent steady speed
The steeper the graph, the greater the
acceleration/deceleration
Uphill sections (/) are acceleration
Downhill sections () are deceleration
A curve represent changing acceleration
The area under the graph represents the distance
travelled
important things to know for distant time graphs
The gradient = speed
flat section are where it’s stopped
The steeper the slope, the faster it is going
Downhill sections means that it’s going towards its
starting point.
Curves represent acceleration
A steepening curve means it’s speeding up
A leaving off curve means it’s slowing down
how to calculate speed
first draw a tangent
then calculate a gradient (change in y divide change in x)
what is acceleration
Acceleration is how quickly something is speeding up
what is terminal velocity
air resistance is equal to gravity
when the object stops accelerating and moves at a constant speed.
what is newtons 1st law
The velocity of an object will only change if a resultant force is acting on the object.
what is newtons 2nd law
The acceleration of an object is proportional to the resultant
force acting on the object and inversely proportional to the mass of the object.
what is newtons third law
when two objects interact, they exert equal and opposite forces on each other
what is stopping distance
distance during the drivers thinking time (notices the object) till he actually applies the break and stops
what is thinking time
– the time taken between
seeing the hazard and hitting the brakes. Typical range 0.4s to
0.9s
what is braking distance
the time taken between applying the brakes and the car stopping.
factors affecting thinking distance
-tiredness
-poor visibility
-too much alcohol
too many drugs
factors affecting braking distance
wet roads
icy roads
driving too fast
tyres/brakes worn out
what is momentum
an object’s mass and velocity
what is the conservation of momentum
In a closed system, the total momentum before an event
is equal to the total momentum after an event.
