Speed Flashcards
What are distance and displacement?
A vector and includes the distance and direction of a straight line from an objects starting point
Distance is how far an object moves and is scalar
What is velocity?
The velocity of an object is its speed in a given direction
An objects velocity changes if it’s direction changes
An object moving in a circle will have a constantly changing velocity
What is acceleration?
The change in the velocity of an object per second (m/s^2)
An object accelerates when it’s speed or direction are changing
Change in velocity/ time taken
What is uniform acceleration?
When the acceleration of an object is constant
Final velocity ^2 - initial velocity ^2 = 2 x acceleration x distance
What is speed?
Speed = distance/ time
Walking ~ 1.5 m/s
Running ~ 3.0 m/s
Cycling ~ 6.0 m/s
Sound ~ 300 m/s
What are drag forces?
When an object moves through a fluid, a frictional drag acts on it, acting in the opposite direction to object movement
Increase with object speed
Depend on shape and size of object
How can you reduce drag?
Streamlining
What is frictional drag in air called?
Air resistance
What is terminal velocity?
An object falling experiences weight and drag
Weight is constant
Drag gets bigger as the object speeds up
The resultant force gets smaller
The acceleration decreases
The object will reach a final steady speed
The constant velocity an object reaches when the frictional force acting on it is equal to weight
What is a velocity time graph?
Shows how velocity of an object changes with time
Straight line = constant acceleration
Curved line = changing acceleration
Horizontal line = constant velocity
Gradient = acceleration
Area = distance travelled
What is a distance time graph?
Shows the distance travelled by an object moving in a straight line over time
Upwards curve = acceleration
Downward curve = deceleration
Horizontal = stopped
Steeper = higher speed
Straight line = constant
Gradient = speed
