Speed vs. Velocity and Graphs

Speed vs. Velocity and Graphs

Year 10

​What we will learn about...

• ​contrast between speed and velocity

• ​explain the difference between and calculate instant and average speed

• ​interpret and construct distance/displacement and time graphs

• ​velocity/speed vs time graphs

Multiple Choice

A train travels 25 km in .5 hrs. How fast is the train going?

• 25 miles/hr

• 5 miles/hr

• 125 km/hr

• 50 km/hr

​Speed vs Velocity

• ​speed = scalar quantity

• ​velocity = vector quantity

• ​you often see the two terms used in place of each other, depending on the resource

​Speed vs Velocity

• ​speed = scalar quantity

  • ​how fast an object is moving

• ​velocity = vector quantity

  • ​how fast an object changes position

  • ​also has a direction

  • ​can be negative

• ​you often see the two terms used in place of each other, depending on the resource

​Instant vs Average Speed

​Instant vs Average Speed

• ​instant speed = the speed of an object in motion at any given moment

• ​average speed = the average taken of all instantaneous speeds (s= d/t)

• ​we don't need to 'calculate' instant speed

Multiple Choice

Calculate the velocity of a car that travels 556 kilometers northeast in 3.4 hours.

• 163.52 km/hr northeast

• 163.52 km/hr

• 0.006 km/hr

• 0.006 km/hr northeast

Multiple Choice

The speedometer on your car tells you

• average velocity

• instantaneous velocity

• average speed

• instantaneous speed

Multiple Choice

At 60 seconds, how far had this object traveled? 

• 0 m

• 10 m

• 20 m

• 40 m

Multiple Choice

What is happening in this graph from point A to B?

• The object is accelerating.

• The object is not moving.

• The object is decelerating.

• The object is moving at a constant speed.

​Distance/Displacement vs Time Graphs

​Displacement vs Time Graphs

​Example Questions:

• ​What is happening to the object between points A and B?

• ​What is the velocity of the object between points O and A?

• ​What is the velocity of the object between points B and C?

• ​What is the overall displacement of the object?

​Velocity vs Time Graphs

Multiple Choice

What does this graph mean?

• no velocity (at rest)

• uniform velocity

• uniform speed

Multiple Choice

Find the velocity from the given graph.

• -2m/s

• $$-\frac{1}{2}\ \ \frac{m}{s}$$

• 2m/s