Motion Chapter 2

Distance How far an object moves

Reference point Determines the object’s position Motion occurs when an object changes its position from the reference point.

Displacement Distance and direction of an object’s change in position from reference point

Speed Distance per time

A car traveling at a constant speed covers a distance of 750m in 25 s A car traveling at a constant speed covers a distance of 750m in 25 s. What is the car’s speed? 30m/s

A dog runs at a speed of 3km/h. How far does he run in 3 hours?

An airplane travels at a rate of 240m/s. How long does it take to travel 560m?

Practice Problems (p.40) 1. A passenger elevator travels from the first floor to the 60th floor, a distnace of 210 m in 35s. What is the elevator’s speed? 6 m/s A motorcycle is moving at a constant speed of 40km/h. How long does it take the motorcycle to travel a distance of 10km? 0.25 h How far does a car travel in 0.75 h, if it is moving at a constant speed of 88km/h? 66km

Average speed TOTAL distance traveled divided by the TOTAL time

Average speed You travel 5 kilometers in 0.25 h (15 minutes). What is your average speed?

Instantaneous Speed The speed at a given point in time

Car Motion lab Calculate the speed of the car. Is this an average speed or instantaneous speed? Explain.

Graphing motion x-axis : time y-axis : distance

Compare & Contrast

velocity Displacement per time Includes direction You walk 500 meters north in 700 seconds. What is your velocity?

Is the speed changing? Is the direction changing? Is the velocity changing?

Calculating velocity 1. A child runs 200 meters east in 190 seconds. Calculate his velocity. 2. A gorilla walks 5 meters to the right of a tree in 8 seconds. What is its velocity? 3. The duck swims 10 meters south in 20 seconds. Find the duck’s velocity. 4. A scuba diver dives down 14 feet in 2 minutes. What is his velocity?

Acceleration Rate of change of velocity 2 types of change: 1. Change in speed Slowing down or speeding up 2. Change in direction

Calculating Acceleration Acceleration= change in velocity / time Change in velocity= final velocity – initial velocity

Acceleration= change in velocity / time SI unit is m/s₂ Change in velocity= final velocity – initial velocity

A cheetah increase sits speed from 2m/s to 6m/s in 2 seconds. What is his acceleration? Is it positive or negative acceleration?

Calculating Negative acceleration An airplane changes speed from 60 m/s to 20 m/s in 8 seconds. What is the planes acceleration?

A jet travels straight down a runway before takeoff A jet travels straight down a runway before takeoff. It travels from rest to 80m/s in 20 seconds. What is its acceleration? A skateboarder moves at 3m/s and comes to a rest during a time period of 2 seconds, What is his acceleration?

P. 51- Roller coaster

Tennis Ball

FOrce A push or a pull Can cause motion to change

Unbalanced force: forces on an object that cause change in motion Balanced force: forces on an object that are equal in size and opposite in direction Net force: sum of forces

Inertia The tendency of an object to resist change in its motion Depends on mass The greater the mass, the greater the inertia

Newton’s first law of motion An object in motion stays in motion unless acted upon by an outside force. An object at rest stays at rest unless acted upon y an outside force. video

Isaac newton