Chapter 11 Flashcards
a system for specifying the precise location of objects in space and time
Frame of reference
An object’s change in position relative to a reference point
Motion
Objects move when their position changes in relation to a ________.
reference point
Distance measures the ______.
Path taken
What is the measure of the path taken?
(Distance) How far an object moves
Displacement is the change of an ______.
Objects position
The change in an objects position with a direction indicator
Displacement
Can distance be a straight line?
Yes
Must displacement be a straight line?
Yes
the distance traveled divide by the time interval during which the motion occurred
Speed
What is the formula for speed?
v=d/t
Why is speed represented with the variable v?
Because the SI units are m/s
What is achieved when an object covers equal distance in equal amount of time?
Constant speed (No change in speed)
What is the triangle for speed?
d
v | t
(t must be cursive and lower cased)
Speed can be studied in _____.
Graphs
The steeper the slope, the ____ the speed the object possesses.
Greater
Time is always on the _ axis, and distance is always on the _ axis.
time, x-axis
distance, y-axis
Slope=
change in y / change in x
How is average speed calculated?
distance/ time
Ex. Calculate the average speed of a runner who runs 132m in a time of 18 sec.
v=d/t 132m/18s= 7.3m/s
What is the speed at a given point in time?
Instantaneous Speed
What describes both speed and direction?
Velocity
What is the speed of an object in a particular direction?
Velocity
Math practice on page 369!!
What is a combination of 2 velocities?
Resultant velocity
Do you add vectors in resultant velocity?
YAS
Airplane flying at 350 km/hr W and a jet stream with a velocity of 55 km/hr E.
Draw Vectors tip to tail.
350-55= 295 km/hr
What shows distance on the vertical axis and time on the horizontal axis?
Plot graphs
Practice graphing on page 370
What equals speed in a plot graph?
The slope of a distance vs. time graph equals speed
-the rate at which velocity changes over time; an object accelerates if it’s speed, direction, or both changes
Acceleration
Uniform circular motion has ____ acceleration.
centripetal
What’s the formula for calculating acceleration?
a= (final velocity - initial velocity)/ time
a=
/\v/t
Math practice on page 375!!!
Can acceleration be determined from a velocity vs. time graph?
YAS
The slope of the line gives the value of _____.
Acceleration
Positive slope=
Increase in acceleration
Negative slope=
Decrease in acceleration
An action exerted on a body in order to change the body’s state of rest or motion; force has both magnitude and direction
Force
What are the four fundamental forces?
Gravity
Electromagnetic
Strong nuclear force
Weak nuclear force
Name two things that can stop an object to move or to stop moving.
Contact forces
Field forces
Give an example of a contact force.
Push a cart
Give an example of a field force.
Gravity
To what direction do objects accelerate?
In the direction of the net force
Do balanced forces change motion?
No
____ forces do not cancel out completely.
Unbalanced
a force that opposes motion between two surfaces that are in contact
Friction
The force that resists the iniation of sliding motion between two surfaces that are in contact and at rest
Static Friction
The force that opposes the movement of two surfaces that are in contact and are moving over each other
Kinetic friction
Name two different types of kinetic friction.
Sliding friction
Rolling friction
Are all kinetic frictions the same?
No
What also opposes motion besides friction?
Air resistance
Give an example of air resistance
Fluid friction
How can harmful friction be reduced?
By lubricants
Helpful friction can be ____.
Increased
