Motion 3.1 Flashcards
What is displacement?
-Displacement is a vector quantity a because it has both size and direction
What is speed and velocity and give equations for both?
-speed is a scalar quantity because it only has a magnitude
-Velocity is a vector quantity because it has both magnitude and direction
-Average speed=total distance travelled/time taken
-Average velocity=total displacement/time taken
How to find total displacement from a displacement time graph?
-How far away the graph finishes from the starting point.
What is acceleration?
-Acceleration is the rate of change of velocity:
-Acceleration=change in velocity/time taken
On a displacement time graph what represents increasing acceleration and deceleration and a constant velocity
-Increasing acceleration and deceleration=curve upwards and curve downwards but still with positive gradient
-Constant velocity=Constant gradient
On a velocity time graph what indicates constant acceleration and deceleration and constant velocity?
-Constant acceleration= diagonal line with positive gradient
-Constant deceleration=Diagonal line with negative gradient
-Constant velocity= line along the x-axis
What is the value for acceleration due to gravity
9.81m/s^2
Why is it better to use motion sensors and light gates than a stopwatch when determining g
-Motion sensors and light gates are more accurate as they remove reaction time
What are the two methods for determining acceleration due to gravity and what conditions are needed?
-Direct approach: timing a ball falling and using equations of motion
-Indirect approaches: for e.g measuring the time taken for a pendulum to do a full swing
-The object needs to be close to the earths surface so it doesn’t reach terminal velocity
What is the equation for stopping distances and the definitions of the other distances it depends on?
-Stopping distance=thinking distance + braking distance
-Thinking distance: the distance the car travels between the driver seeing the hazard and applying brakes
-Braking distance: distance car travels between applying brakes and coming to rest
Factors that increase thinking distance?
-Higher speed
-Age of driver
-Distractions
-drugs and alcohol
-tiredness
What is the equation for thinking distance?
-Thinking distance= reaction time of driver * speed of car
Factors that increase braking distance?
-Higher speed
-Conditions of brakes and tires
-mass of car
-Poor road conditions (icy)
