Speed and Velocity Homework Speed is a way to describe the motion of an object. Speed refers to "how fast an object is moving." A fast-moving object has a high speed while a slow-moving object has a low speed. An object with no movement at all has a zero speed. Velocity is "direction-aware." When evaluating the velocity of an object, one must keep track of direction. It would not be enough to say that an object has a velocity of 55 mi/hr. you must include direction information in order to fully describe the velocity of the object. For instance, you must describe an object's velocity as being 55 mi/hr, east. This is one of the essential differences between speed and velocity. Speed does not keep track of direction; velocity is direction-aware. The task of describing velocity is easy! If an object is moving downwards, then its velocity is described as being downwards. So an airplane moving towards the west with a speed of 300 mi/hr has a velocity of 300 mi/hr, west. Note that speed has no direction and velocity is simply the speed with a direction. Describing Motion The motion of objects can be described by words - words such as distance, speed and velocity. Each of these terms has a different meaning. • • •

Distance = How far an object travels Speed = Distance/Time Velocity = Speed with a direction

To test your understanding of this distinction, consider the following quantities listed below. Categorize each quantity as being distance, speed or velocity.

Quantity 5 meters 30 meters/hour 200 miles 50 miles/hour North 55 mph 100 cm 400 meters/minute Southeast 1 kilometer 55 miles/hour West

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Speed and Velocity Homework Speed is a way to describe the motion of an object. Speed refers to "how fast an object is moving." A fast-moving object has a high speed while a slow-moving object has a low speed. An object with no movement at all has a zero speed. Velocity is "direction-aware." When evaluating the velocity of an object, one must keep track of direction. It would not be enough to say that an object has a velocity of 55 mi/hr. you must include direction information in order to fully describe the velocity of the object. For instance, you must describe an object's velocity as being 55 mi/hr, east. This is one of the essential differences between speed and velocity. Speed does not keep track of direction; velocity is direction-aware. The task of describing velocity is easy! If an object is moving downwards, then its velocity is described as being downwards. So an airplane moving towards the west with a speed of 300 mi/hr has a velocity of 300 mi/hr, west. Note that speed has no direction and velocity is simply the speed with a direction. Describing Motion The motion of objects can be described by words - words such as distance, speed and velocity. Each of these terms has a different meaning. •

Distance = ________________________________________________________

•

Speed = __________________________________________________________

•

Velocity = ________________________________________________________

To test your understanding of this distinction, consider the following quantities listed below. Categorize each quantity as being distance, speed or velocity. Quantity 5 meters 30 meters/hour 200 miles 50 miles/hour North 55 mph 100 cm 400 meters/minute Southeast 1 kilometer 55 miles/hour West

Category

Vector Diagrams In Physics, vector diagrams are often used to describe the velocity of a moving object during its motion. For example, the velocity of a car moving down the road could be represented by a vector diagram.

Vectors are quantities which are fully described by both a distance traveled and a direction. The way this works is that you draw a picture with lines or arrows representing different distances.

Velocity is often represented by a scaled vector diagrams. Vector diagrams depict a vector by use of an arrow drawn to scale in a specific direction.

An arrow (with arrowhead) is drawn in a specified direction; therefore, the vector has a head and a tail. The speed and direction of the vector is clearly labeled; in this case, the diagram shows the speed is 12 m/second and the direction is Northwest

1. Given the SCALE: 1 cm = 10 m/s, determine the speed and direction that a bike traveled.

2. Given the SCALE: 1 cm = 50 km/hr, determine the speed and direction that a car traveled. .

3. Given the SCALE: 1 cm = 10 m/minute, determine the speed and direction that a jogger traveled.

4. Given the SCALE: 1 cm = 25 km/hr, determine the speed and direction that a car traveled.

5. Given the SCALE: 1 cm = 10 miles/hour, determine the speed and direction that a car traveled.

6. Given the SCALE: 1 cm = 100 miles/hr, determine the speed and direction that a plane traveled.

7. The trip in the diagram below takes approximately 2 hours and covers approximately 1900 km. 1. What is the speed of the plane?

2. What is velocity of the plane?

3. What is the difference between speed and velocity?