motion

• What is a scalar quantity?

  A quantity that only has magnitude and no direction.

  e.g. mass, temperature, volume
• What is a vector quantity?

  A quantity that has a magnitude and a direction.

  e.g. force, weight, velocity
• What is displacement?

  the change in position from one place to another.

  It is the shortest distance between 2 points and has a direction
• What is the difference between average speed and instantaneous speed?

  The average speed is for the whole journey but the instantaneous speed is the speed at a particular point on the journey.
• What are the typical speed values for walking, running and cycling?

  Walking: 1.5 m/s

  Running: 3 m/s

  Cycling: 6 m/s
• this graph shows the object at a constant speed because it's a straight line.

  B is faster than A

  Speed = gradient

  
• this graph shows that the object is stationary.

  Gradient = 0

  Speed = 0

  
• this graph shows that the object is accelerating

  the gradient gets steeper so the speed increases

  
• this graph shows the object is going at a constant speed backwards

  
• What is acceleration?

  the rate of change of velocity, or how much an object's velocity changes each second.
• This graph shows the object at constant acceleration

  A is accelerating at a lower rate than B

  Acceleration = gradient

  
• this graph shows the object at a constant velocity

  gradient = 0

  acceleration = 0 m/s

  
• this graph shows the object at constant deceleration

  gradient is negative

  
• This graph shows A is at constant deceleration

  stationary at point x

  velocity = 0 m/s

  B is constant acceleration backwards

  
• how to find the displacement from a velocity time graph?

  calculate the area under the graph
• what is speed?

  the rate of change of position of an object in any direction
• why is the speed of a moving object rarely constant?

  for an object to move a constant speed, its must experience 0 net force. Forces cause acceleration which changes the speed.

  Friction and air resistance slow things down

  energy input isn't perfectly steady: a person walking or running will be fatigued.
• what are some factors that can affect the speed a person can walk, run or cycle?

  fitness level

  age

  stride length

  skill/technique

  gender
• what is the equation linking distance, speed and time?

  distance = speed x time
• what is velocity?

  A vector quantity that describes an objects speed in a specific direction
• explain why an object moving in a circle, at a constant speed, has a changing velocity

  the velocity changes because the direction changes
• what is the equation linking acceleration, change in velocity and time?

  acceleration = change in velocity/ time
• what is the equation linking acceleration, initial velocity, final velocity and distance?

  final velocity = initial velocity + 2 x acceleration x distance
• typical speed values for walking

  1.5 m/s
• typical speed values for running

  3 m/s
• typical speed values for cycling

  6 m/s