P10 - Momentum + Velocity Flashcards
resultant force formula
mass x acceleration
unit for acceleration
m/s^2
Newton’s second law of motion
acceleration:
is proportional to resultant force
inversely to mass
Inertia
tendency of object to stay at rest or continue in uniform motion
inertial mass
measure of difficulty of changing the object’s velocity
inertial mass formula
force/acceleration
positive acceleration
velocity increases
force is same direction as velocity
negative acceleration
velocity decreases
force is in opposite direction
Greater resultant force on object
greater object’s acceleration
Greater mass =
smaller acceleration
weight
force acting on it due to gravity
mass
depends on quantity of matter
gravity
9.8
weight formula
gravity x mass
terminal velocity formula
force = weight - frictional force
terminal velocity meaning
object reaches a constant velocity when force on it is equal and opposite to its weight
-resultant + acceleration = 0
-weight = frictional force
velocity of object acted on by only gravity
10
braking force depends i=on
speed of vehicle
-mass
greater speed =
greater deceleration
greater mass =
greater braking force
stopping distance
shortest distance a vehicle can safely stop in
thinking distance
distance travelled by vehicle in the time it takes driver to react
thinking distance formula
speed x reaction time
braking distance
distance travelled by vehicle during time braking force acts in it
stopping distance formula
thinking + braking distance
factors affecting stopping distnace
-alcohol/ drugs
-tiredness
-thinking distance
-weather
-worn brakes
-speed
acceleration formula
a = v^2 - u^2/2s
v = final velocity
u = initial velocity
s = distance
braking force formula
f = ma
momentum unit
kg m/s
momentum formula
mass x velocity
momentum vector or scalar
vector
size and direction
conservation of momentum
total before = total after an event in a closed system
-no resultant force acts on it
momentum of object A =
- momentum of obejct B
momentum of A + momentum of B =
0
longer impact time =
more impact force is reduced
force, mass, velocity, time formula
f = m x v /t
when vehicles collide, force of impact depends on
mass
velocity
length of impact time
when 2 vehicles collide
they exert equal and opposite forces on each other
-total momentum is unchanged
impact force formula
change of momentum /impact time
shorter impact time =
greater force
cycle helmet + cushioned ground safety
reduces impact
-increases impact time
seat belts + air bags safety
spread force across chest
-increase impact time
crumple zones safety
give way in impact
increase impact time
elastic
can bend back to shape
when forces deforming it are removed
extension
increase of length from original
extension of strip formula
length at stage - original length of spring
Hooke’s Law
-extension is directly proportional to force
-as long as limit of proportionality isn’t exceeded
limit of proportionality
cannot bend back into shape
Hooke’s law formula
f = ke
stiffer the spring =
greater the spring constant
beyond the limit of proportionality = which type of relationship
non-linear
