Motion
by emily esser
1. Acceleration
1.1. the rate of change of the velocity
1.2. indicates any change in the velocity vector
1.2.1. change in direction
1.2.2. increase in speed
1.2.3. decrease in speed
1.2.4. simultaneous change in speed and direction
1.3. To find it:
1.3.1. the change in velocity divided by the corresponding time interval
1.3.2. meters per second squared
1.4. Reading graphs
1.4.1. net force and velocity point in opposite directions=slowing down
1.4.2. Net force and velocity point in same direction= speeding up
1.4.3. Straight-line motion= acceleration is wither same direction as velocity or in the opposite direction to the velocity
2. Position
2.1. States where an object is located
2.2. x-, y-, and z-coordinates
2.3. Point of reference in relation to origin
2.3.1. Direction
2.3.2. Distance
3. Displacement
3.1. Definition:The change of the position vector
3.2. How to find it: The final position vector minus the initial position vector
3.3. Remember: does not necessarily equal the total distance traveled
4. Velocity
4.1. depends on displacement and time interval
4.2. Average velocity
4.2.1. does not reveal information about the motion during the time interval
4.2.2. product of the vector, the displacement, and a positive scalar, the inverse of the time interval
4.2.3. x-axis
4.2.3.1. represented on the graph as x(t)
4.3. Instantaneous velocity
4.3.1. a vector
4.3.2. magnitude is the speed
4.3.3. direction of motion
4.3.4. used to calculate the displacement of the object during a very short interval
4.4. Reading Graphs
4.4.1. sloping portions on graphs indicate=movement
4.4.2. a horizontal position=position has not changed
4.4.3. steeper the graph=faster speed
4.4.4. sign of the slope indicates direction of motion
4.4.4.1. positive slope
4.4.4.2. positive slope=motion in the +x-direction
4.4.4.3. negative slope=motion in the -x-direction
5. Newton's second law
5.1. rate of change of the velocity is proportional to the net force and inversely proportional to the mass of th object
5.2. net force is constant the acceleration is also constant
5.3. Applying to problems
5.3.1. Decide what objects will have Newton's second law applied to them
5.3.2. Identify all the external forces acting on that object
5.3.3. Draw a FBD to show all the forces acting on the object
5.3.4. Choose a coordinate system
5.3.5. find the net force by adding the forces as vectors
5.3.6. Relate the net force to acceleration
5.3.7. Relate the acceleration to the change in the velocity vector during a time interval of interest
6. Constant net force
6.1. equations
6.1.1. change of velocity is equal to the final velocity minus the initial velocity = acceleration times the change in time
6.1.2. refer to page 108 and 109
7. Visualization
7.1. Motion diagrams
7.1.1. position
7.1.2. velocity
7.1.3. Acceleration
8. Free Fall
8.1. No forces act on an object other than the gravitation force that makes the object fall
8.2. Air resistance
8.2.1. neglible
8.3. massive objects are harder to accelerate
8.4. More mass=more inertia
8.5. the acceleration of an object in free fall is the vector of "g" regardless of the object's mass
8.6. 9.80 meters per second squared
9. Motion of projectiles
9.1. an object moves in the xy-[plane with constant acceleration then both a of x and a of y are constant
9.2. Projectiles
9.2.1. objects in free fall
9.2.2. motion takes place in vertical plane
9.3. Angle of elevation
9.3.1. angle of initial velocity above the horizontal
9.4. Trajectory
9.4.1. path it takes in air
10. Apparent Weight
10.1. the feeling of "weightless"
10.2. elevator example
10.2.1. upwards the weight will be great than the true weight
10.2.2. downwards the weight will be less than the true weight
11. Air resistance
11.1. Drag force
11.1.1. increases as speed increases
11.1.2. the larger the surface area the more air is needed to be pushed out of the way
11.2. Terminal velocity
11.2.1. the acceleration is zero
11.3. Terminal speed
11.3.1. the magnitude of the terminal velocity is:
11.3.2. depends on:
11.3.2.1. size
11.3.2.2. shape
11.3.2.3. mass
12. Vectors
12.1. Positions and displacements
12.2. Problem solving
12.2.1. Vectors in different direction, Subtraction: is to add its opposite
12.2.1.1. has same magnitude but opposite direction
12.2.2. Multiplication
12.2.2.1. multiplyig a vector by the scalar -1 reverses the vector's direction while magnitude is unaffected
12.2.3. Subtraction : used to find displacement
13. Words of the Day
13.1. Forestall
13.1.1. to predict what is ahead
13.2. Modus operandi
13.2.1. "mode of operation"
13.3. Ne Plus ultra
13.3.1. the most profound degree
13.4. Ithaca
13.4.1. the journey
13.5. Panacea
13.5.1. cures
13.6. Explore
13.6.1. To investigate systematically; examine
13.7. Red Herring
13.7.1. something intended to divert attention from the real problem or matter at hand
13.8. Mash-Up
13.8.1. combining data from more than one source into a single integrated tool
14. Helpful terms
14.1. Interval
14.1.1. The amount of time between two specified instants, events, or states
14.2. Slope
14.2.1. rise/run
14.3. Mass
14.3.1. measure of its inertia
14.4. Weight
14.4.1. is the magnitude of the gravitational force acting on it