Scalars & Vectors
Speed is this kind of quantity.
A scalar
Drawing a line from the start of the first arrow to the end of the second.
The triangle method
The horizontal and vertical pieces of a diagonal arrow.
Components
Motion through the air under gravity.
Projectile motion
Velocity is this kind of quantity.
A vector
Vectors can be added in any order.
The commutative property
The theorem that gives the length of a right-angle resultant.
The Pythagorean theorem
The shape of a projectile’s path.
A parabola
Italics mark this kind of quantity.
A scalar
Double a 2 m/s south velocity and you get this.
4 m/s south
The trig function used to find a resultant’s angle.
Tangent
Sideways velocity of a projectile (air resistance ignored).
Constant
Bold marks this kind of quantity.
A vector
Cosine of the angle times the diagonal gives this piece.
The x-component
Sine of the angle times the diagonal gives this piece.
The y-component
Vertical acceleration of a projectile compared with a dropped object.
They are the same
A reading that includes both how fast and which way.
A vector
A boat heads north while the current pushes east. From shore the path is found by doing this to the two velocities.
Adding them as vectors
Why two people can disagree about the same object’s velocity.
Different frames of reference
Initial vertical speed of a ball rolled straight off a cliff.
Zero