Physics - chapter 3

What is another way of saying -30 m/s west?

30 m/s east

Vector (Definition)

A physical quantity that has both direction and magnitude

Scalar (Definition)

A physical quantity that has only magnitude but no direction (specified only by a number with appropriate units)

Cosines of an angle

Adjacent leg/hypotenuse

Vector (Examples)

Displacement; velocity is also a vector quantity; acceleration; a particular path to be followed

Projectile motion

Free-fall with an initial velocity (neglecting air-resistance) - has a constant horizontal velocity and a constant downward free-fall acceleration

What is the relationship between instantaneous speed and instantaneous velocity?

Instantaneous speed is a scalar quantity, there is no direction involved. Instantaneous velocity is a vector quantity, it has a magnitude and a direction.

Tangent of an angle

Opposite leg/adjacent leg

Sine of an angle

Opposite leg/hypotenuse

Laws of sines

Sine <A / a = Sine <B / b = Sine <C / c

Scalar (Examples)

Speed; volume; amount (the number of pages in a book)

Component vector

The projections of a vector along the areas of a coordinate system (x,y)

The magnitude of a vector is a scalar. Explain this statement.

The quantity by which something moves in a certain direction does not depend on direction. For instance - a car that traveled 30 miles southeast traveled 30 miles regardless of what direction it went.

If two vectors have unequal magnitudes, can their sum be zero? Explain.

Two vectors cannot sum to zero unless they have the same magnitude in exact opposite directions.

Is it possible to add a vector quantity to a scalar quantity?

You cannot add a vector quantity and a scalar quantity - the second quantity must have a direction also. It is possible to multiply a vector quantity and a scalar quantity.

Vector A is 3.00 units in length and points along the positive X axis. Vector B is 4.00 units in length and points along the negative Y axis use graphical methods to find the magnitude and direction of the following vectors: a. A + B b. A - B c. B - A d. A -2B

a (since A and B are perpendicular)

Each of the displacement vectors, A and B, has a magnitude of 3.00 m. Use graphical methods to find the magnitude and direction of the following vectors: a. A+B b. A-b c. B-A d. A-2B

a. A+B=5 ; 53 degrees with the x-axis

Pythagorean theorem

a^2 + b^2 = c^2

Laws of cosines

a^2 = b^2 + c^2 - 2(b)(c)*cos<A

Vector (Property)

m/s; m/s^2; m