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