3.1 Motion Flashcards
What is speed and state its unit
The rate of change of distance
Metres per second (ms -1)
What is instantaneous speed
Speed at a given point
What is velocity and sate its unit
The rate of change of displacement
Metres per second (ms -1)
What is acceleration (a) and state it’s unit
The rate of change of distance
Metres per second (ms -1)
What does the gradient show on a distance/displacement time graph
The speed / velocity
Flat line - stationary
Straight line - constant motion
Curve - accelerating
What does the gradient show on a velocity time graph
Acceleration
Flat line - constant velocity
Straight line - constant acceleration
Curve - changing acceleration
What does the area beneath the graph represent on a velocity time graph
The displacement of the object
What does SUVAT refer to
s - displacement (m)
u - initial velocity (ms -1)
v - final velocity (ms -1
a - acceleration (ms -2)
t - time (s)
What are the SUVAT equations
v = u + at
s = 1/2( u + v )t
v 2 = u 2 + 2as
s = ut + 1/2(at 2)
s = vt - 1/2(at 2)
When can SUVAT equations be used
When acceleration is constant
What is stopping distance
Total distance travelled from when the driver sees the hazard to when the car comes to a complete stop
What is the equation for stopping distance
Stopping distance = thinking distance + braking distance
What is thinking distance
The total distance travelled between seeing the hazard and applying the brakes
What is braking distance
The total distance travelled between applying the brakes and coming to a complete stop
What is the equation for thinking distance
Thinking distance = initial speed x reaction time
What factors affect reaction time
Tiredness
Drugs
Alcohol
Caffeine
Distractions
What is the equation for braking distance.
Braking distance ∝ initial speed 2
What factors affect braking distance
Road conditions
Tyre conditions
Weather
Mass of car
Conditions of brakes
Initial speed
