P9 Flashcards
Wgat is the difference between distance and displacement
Distance is how far an object moves. Distance does not involve direction. Distance is a scalar quantity.
Displacement includes both the distance an object moves, measured in a straight line from the start point to the finish point and the direction of that straight line. Displacement is a vector quantity.
What is speed and how does it vary
Speed is a scalar quantity.
The speed of a moving object is rarely constant. When people walk, run or travel in a car their speed is constantly changing
Speed of sound and wind can also vary
What does speed of a person depend on
The speed at which a person can walk, run or cycle depends on many factors including: age, terrain, fitness and distance travelled
What are typical speeds of walking, running and cyclint
walking ̴ 1.5 m/s
running ̴ 3 m/s
cycling ̴ 6 m/s.
What is the equation for speed
Speed = distance/ time
What is velocity
The velocity of an object is its speed in a given direction. Velocity is a vector quantity
How does motion in a circle effect speed and velocity
Motion in a circle involves constant speed but changing velocity
How can a distance time graph used and how is speed and acceleration calculated on it
If an object moves along a straight line, the distance travelled can be represented by a distance–time graph
The speed of an object can be calculated from the gradient of its distance–time graph
If an object is accelerating, its speed at any particular time can be determined by drawing a tangent and measuring the gradient of the distance–time graph at that time
How is average acceleration calculated
acceleration = change in velocity/ time taken
How do you calculate acceleration and distant on a velocity time graph
The acceleration of an object can be calculated from the gradient of a velocity–time graph
The distance travelled by an object (or displacement of an object) can be calculated from the area under a velocity–time graph
What is the equation for uniform acceleration worked out
v^2 − u^2 = 2 a s ( rearrange )
How is a falling object accelerated and by how much is it accelerated by
Near the Earth’s surface any object falling freely under gravity has an acceleration of about 9.8 m/s^2
How does a falling object reach terminal velocity
An object falling through a fluid initially accelerates due to the force of gravity. Eventually the resultant force will be zero and the object will move at its terminal velocity
Typical speeds for a car, train and plane
Car: 25m/s
Train: 55m/s
Plane: 250m/s
What factors effect speed of sound and wind
Sound is effected by what the waces are travelling through
Wind speed can be effected by temperature, atmospheric pressure and if there are any structures nearby such as large buildings or forests
