forces and motion Flashcards
average speed =
measurement=
distance moved / time taken
m/s
Velocity is a
speed in a defined direction
acceleration =
a =
change in velocity / time taken
v-u / t
distance travelled (velocity-time graph)
Area under the graph
v^2 =
u^2 + 2as
resultant force
When a system of forces is acting on an object, the difference between the forces is called the Resultant force.
Or all the forces added if in same direction
newton first law
when the resultant force acting on an object is zero, the forces are balance and the object does not accelerate.
Acceleration is proportional to
resultant force
acceleration is inversely proportional to
Mass
F =
MA
acceleration measured in
m / s^2
Weight =
W =
mass x gravitational field strength
mg
Thinking distance =
reaction time x speed
Hooke’s law
Force =
F =
spring constant x extension
k x e
Spring constant measurement
Extension measurement
N / m
M
Momentum =
mass x velocity
force =
given in exam, relating to momentum
change in momentum / time taken
Conservation of momentum
When two bodies collide, the total momentum they have is the same after the collision as it was before the collision
Turning moment =
force x perpendicular distance from the pivot
In equilibrium
the sum of the anti-clockwise moments = the same of the clockwise moments
the sum of the forces balance
Stopping distance =
Breaking distance + stopping distance
Factors affecting breaking distance
tyres worn
surface of road
downhill
Factors affecting thinking distance
sleepy
drugs or alcohol
distracted
Breaking distance depend on
speed and mass of car
Newtons second law
resultant force = mass x acceleration
Newtons third law
To every force there is an equal and opposite force
