Dynamics

Scalars and Vectors

How can a boat navigate pass the canal without knocking onto the sides?

Knock!!

Knock!!Knock!!

Knock!!

Locomotives on both sides pulls the ship so they eventually move forward

Scalars and Vectors

Objectives: state what is meant by scalar and vector

quantities and give common examples of each

add two vectors to determine a resultant by a graphical method

solve problems for a static point mass under the action of 3 forces for 2-dimensional cases (a graphical method would suffice)

Scalars and Vectors

Vector quantities have magnitude and direction.

Scalar quantities only have magnitude.

Vectors Scalars

Weight Mass

Velocity Speed

Displacement Distance

Scalars and Vectors

Adding Vectors to find Resultant Vectors (One Dimension):

Car travels 3m right and 1m left

3m

1m2m

0.5m

Scalars and Vectors

Adding Vectors to find Resultant Vectors (Two Dimension):

Rocket travelling up at 3ms-1 and right at 4ms-

1

3ms-1

4ms-1

5ms-1

1ms-1

Scalars and Vectors

ExampleFind the resultant force on the object below

3N

2N 5N

2N

3N

5N

4.2N

1N

Scalars and Vectors

Example (Parallelogram Rule)Find the resultant force of the two forces given below.

3N

2N

objectVectors must

retain direction and magnitude

1N

Scalars and Vectors

ExampleIn which direction should a force be added to the diagram below so that the object will not move.

1N

1N

1N

1N

1.41N

0.5N

Scalars and Vectors

Conclusion Vector quantities have magnitude

and direction. Resultant vector is found by adding

component vectors one after another or by a parallelogram method in a scale diagram.