Distance and Displacement

Distance and Displacement

Ch. 11. 1

True False Statement True False

A frame of reference is objects moving with respect

to one anotherDistance is the length

between 2 points and the direction

Displacement is the added length of all points and the

directionTo add straight

displacements you add the vectors

To add non straight lines you use the resultant vector and Pythagoreans theorem

Frame of Reference Helps describe

motion accurately and completely

A system of objects NOT moving with respect to one another

Relative Motion Movement in

relation to a frame of reference

Ex: Train▪ Platform- people on

train are moving▪ In train- people are

not moving

Measuring Distance

Distance= the length of a path between 2 points

SI Unit- meterkilometer- large distancecentimeter- small distance

Measuring Displacement

Displacement= direction from start point and length of a straight line from start to end point

Travel 5 blocks north of the bus stop

Combining Displacements Vector= quantity that has magnitude

and direction Magnitude= size, length, or amount Shown as arrows on maps/graphs

Add displacements by adding vectors

Combining Displacements-Straight Lines

Add magnitudes if 2 vectors have same direction

Ex: 1st car magnitude= 4km(pg 330)

2nd car magnitude= 2 kmBoth traveling same direction

= ____ km displacement Opposite traveling direction

= ____km displacement

Combining Displacements- Not straight lines

Add total distance Draw resultant vector

Vector sum of 2 or more vectors Also displacement

Pg 331- Walked 7 blocks Displacement= 5 blocks

NE

*Integrating Math-Pythagorean theorem

a2 + b2 = c2

Find distance traveled and displacement

Speed and VelocityCh. 11.2

True False Statement True False

Speed is distance/time and the SI unit is m/s

Velocity is speed with direction and the SI unit is

m/s2

Velocity has the same formula as speed

Because velocity is a vector we can use Pythagoreans

TheoremThe slope of a distance time

graph is velocity

Speed

Speed= the ratio of the distance an object moves to amount of time the object moves

SI Unit- meters per secondm/skm/h

2 Types of Speed

2 Types of Speed

AVERAGE SPEED

Speed computed for entire duration of trip

v = d t

INSTANTANEOUS SPEED Speed at a particular

instant Can tell you how long

your trip will take Speedometers

Calculating Speed PracticeWhile traveling on

vacation, you travel 35 km in 0.4 hours, then 53 km in 0.6 hours. What is your average speed?

1. Given InfoTotal distance:Total time:

2. Solveneed speed

3. Plug and chug

4. Check

Math Practice pg 333

1.

2.

Graphing Motion

Slope of a line on a distance-time graph is speed

Pg 334 Calculate slope of A= B= C=

Velocity

Velocity= the speed and direction in which an object is moving Description of BOTH speed and direction Vector

Change in velocity Change in speed, direction or both

Race car traveling 120 km/h

Speed, direction, velocity?

Combining Velocity

2 or more velocities added by vectors

River= 5 km/h Boat= 12 km/h Total velocity=

pg. 337

River= 5 km/h Boat= 12 km/h Total Velocity=

AccelerationCh. 11.3

True False Statement True False

Acceleration is a change in speed, direction or both

a = vi – vf t

An object slowing down is accelerating

An object in a circle, at constant speed is

acceleratingAcceleration can be a time-speed graph or distance-

time graph

Acceleration

The rate at which velocity changes Changes in speed, direction or both vector

Acceleration

CHANGE IN SPEED

Increase or decrease in speed

Free fall- movement of object toward Earth due to gravity(9.8m/s2)

SI unit- m/s2

CHANGE IN DIRECTION

Speed can be constant, but a change in direction yields acceleration

AccelerationCHANGE IN SPEED & DIRECTION

CONSTANT ACCELERATION Steady change in

velocity

Calculating Acceleration

Acceleration Practice

A ball rolls down a ramp, starting from rest. After 2 seconds its velocity is 6m/s. What is the acceleration of the ball?

1. Given InfoTime-Vi-Vf-

2. Plug and Chugacceleration-?

3. Check

Math Practice pg 346

1.

3.

2.

4.

Graphs of Acceleration

Slope of speed-time graphs is acceleration

Change in speed divided by change in time

Graphs

SPEED-TIME GRAPH

Linear graphs

DISTANCE-TIME GRAPH

Nonlinear graphs

Instantaneous Acceleration How fast a velocity is changing at a

specific instant

Review

ReviewMotion

displacement

acceleration

direction Change in speed