Forces - Forces & Motion Flashcards
what does displacement measure
vector quantity that measures distance and direction in a straight line from the objects starting point
what is the difference between speed and velocity
velocity includes direction
what does an object have that is moving in a circle at a constant speed
constantly changing velocity
what are the typical speeds for walking running cycling
walking 1.5m/s
running 3m/s
cycling 6m/s
what are the typical speeds for a car train and plane
car 25m/s
train 55m/s
plane 250ms
what is the equation for speed (m/s)
distance (m)/ time(s)
what is acceleration
how quickly the velocity is changing
this can be a change in speed, direction or both
what is the equation for acceleration (m/s2)
change in velocity / time (s)
what does the gradient show on a distance time graph
speed
what does a curve represent on a distance time graph
acceleration
how do you work out the speed at a certain time when the object is accelerating
draw a tangent on the curve
what axis does velocity go on a velocity time graph
y axis
what does the gradient of a velocity time graph show you
acceleration
what does a cure tell you on a velocity time graph
increasing acceleration
how can distance be found on a velocity time graph
its the area under the line
what direction does friction act in
opposite direction of movement
what is a streamlined object
allows fluids to flow over it easily so the object isnt slowed down as
much by friction
why does a cars engine have to work harder to maintain a steady speed at 70mph than at 20mph
frictional forces from fluids always increase with speed
why does an object accelerate when it starts to fall
force of gravity is greater than frictional forces, however when it moves faster the frictional forces become greater until its balanced ( terminal velocity)
what is a factor that effects terminal velocity
shape and area of object
the gravitational force
what is newtons first law
if an object has a 0 resultant force it will remain in its current state of movement
what are 5 ways an object can show a change in velocity
starting stopping speeding up slowing down changing direction
what is the equation that shows newtons second law
force (N) = m(kg) x acceleration(m/s2)
explain newtons second law
the larger the resultant force the more an object accelerates so force and acceleration are directly proportional
what is the relationship between mass and acceleration
an object w a larger mass will accelerate less so the are inversely proportional to each other
what is the tendency to remain in the same state of motion called
inertia
what is an objects inertial mass
how difficult it is to change the velocity of an object
how do you work out inertial mass
m = f/a
what is newtons third law
when 2 objects interact, the forces they exert on each other are equal and opposite
