5.6 Describing Motion

• What is distance a measure of?

  How far an object travels
• Why is distance considered a scalar quantity?

  Direction is not important in distance
• What does displacement measure?

  How far something is from its starting position
• Why is displacement considered a vector quantity?

  It describes both magnitude and direction

  
• What is the displacement of the athletes at the end of the race?

  100 m to the right
• What would be the final displacement if the athletes ran 400 m?

  Zero displacement
• What is speed a measure of?

  The distance an object travels every second
• Why is speed considered a scalar quantity?

  It only contains magnitude without direction
• What is the unit of speed?

  Metres per second (m/s)
• What does non-uniform motion refer to?

  Motion that is changing in speed or direction
• Why do race drivers need to understand non-uniform motion?

  They slow down for corners and speed up on straights
• What is the typical speed of a person walking?

  About 1.5 m/s
• What factors affect typical walking speeds?

  Age, terrain, fitness, distance
• What is a typical speed of sound in air?

  330 m/s
• What is a typical speed of sound in seawater?

  Around 1500 m/s
• How can speed be measured accurately?

  By timing how long it takes to travel a known distance

  
• What equipment can be used to measure distance accurately?

  A tape measure or trundle wheel
• How do light gates measure speed?

  They start and stop a timer as objects pass through

  
• What does a single light gate measure?

  The speed of an object as it passes through

  
• What is the equation for calculating speed?

  Speed = distance ÷ time

  
• How do you convert hours into seconds?

  Multiply by 3600
• What is the average speed of Florence Griffith Joyner during her record race?

  9.53 m/s
• What is the difference between speed and velocity?

  Velocity includes direction, speed does not
• Why is velocity considered a vector quantity?

  It describes both magnitude and direction
• How does circular motion affect velocity?

  Velocity changes due to changing direction
• What does a distance-time graph represent?

  How distance varies over time for an object

  
• What does a straight line on a distance-time graph indicate?

  Constant speed

  
• What does a steep slope on a distance-time graph indicate?

  Large speed

  
• What does a flat line on a distance-time graph indicate?

  The object is stationary
• What does a shallow slope on a distance-time graph indicate?

  Small speed

  
• What does changing speed on a distance-time graph indicate?

  The object is accelerating or decelerating

  
• How can you interpret a distance-time graph?

  By analyzing the slope and shape of the line

  
• What does a distance-time graph show?

  Distance varies over time for an object

  
• What does a straight line on a distance-time graph represent?

  Constant speed of the moving object

  
• What does the slope of a straight line on a distance-time graph indicate?

  The magnitude of the speed

  
• What does a very steep slope on a distance-time graph indicate?

  The object is moving at a large speed

  
• What does a shallow slope on a distance-time graph indicate?

  The object is moving at a small speed

  
• What does a flat, horizontal line on a distance-time graph represent?

  The object is stationary (not moving)

  
• How is changing speed represented on a distance-time graph?

  By a curve on the graph

  
• What does an increasing slope on a distance-time graph indicate?

  The speed is increasing (accelerating)