Motion

Recognizing Motion• An object is in motion

when its distance from another object is changing.

• Whether an object is moving or not depends on your point of view, or, which reference point you’re using.

• A reference point is a place or object used for comparison to determine if something is in motion.

Ex) If you are standing still you may conclude that you are not moving because your distance is not changing from what you can observe

…however…When considering that you are standing on a planet that is moving at 30Km every second…you’re moving very fast!!!

Distance

• To describe motion further we need to use units of measurement.

• The basic unit for length is the meter (m), according to the International System of Units (SI), also known as the metric system.

Calculating Speed• To calculate the speed

of an object, you need to know how much distance it travels in one unit of time.

Solve• A horse is moving at a constant speed. • Find its speed if it canters 21 meters in 3 seconds.

1.Write out the formula. Speed = distance / time.

2.Substitute in the values for distance and time.

3.Solve the equation.4.Use appropriate units to label your answer!!!

Solution

1. Speed = d/t2.S = 21 m / 3 s3.S = 74.S = 7 m/s

Solve• A cyclist travels 32 kilometers (km)

in the first 2 hours and another 13 km in the next hour.• The average speed of the cyclist is

the total distance of the trip divided by the total time it took.• Use steps 1-4 to solve.

Solution1. Average speed = total distance / total

time2. S = 45 km (32km + 13km) / 3 h (2h+1h)3. S = 45km / 3h = 15 4. 15 km/ h

Describing Velocity

• Velocity is simply the speed of an object in a given direction.

Ex) The winds velocity was 25 mph (miles/hour) northwest.

Do Now!!!• Mrs. Linton arrived at school this morning in

her brand new Ferrari. She lives 25 miles away and it took her 10 minutes to get here. How fast was she driving?

• Remember!!! 1.Write the formula2.Substitute in values3.Show work4.Solve with the appropriate units

Solution

• S = d/t• S = 25 miles / 10 minutes• S = 2.5 miles / minute

Graphing Motion• You can show

the motion of an object on a line graph in which you plot distance against time.

Speed = d / t

Constant Speed

No Motion

Accelerating Motion

• Acceleration • Deceleration

Do Now !!!Mr. Fox wanted to ride his moped to work which was 13 miles south of his home. He left home at 6:59am and rode until he reached the bagel store at 7:07am. He then left the bagel store at 7:12am and continued to JW Bailey. It was 7:24am when he parked. What was his average velocity?

Solution1. V = d/t

2. V = 13 miles south = 13 miles south8 min. + 12 min. 20 min.

3. V = .65 miles/ min. south

Acceleration• Acceleration is the

rate at which velocity (speed) changes.

• In science, acceleration refers to increasing speed, decreasing speed, or even just changing direction!

Acceleration by Changing Direction• The Earth is constantly accelerating around the sun

because it is constantly changing direction.

Graphing Acceleration

OR

Be careful!!! Acceleration may be shownBy plotting distance vs. time, OR, speed vs. time!!!

SolveA roller coaster accelerates down a slope from 4 m/s

(meters per second) to 22 m/s over the time span of 3 seconds. What is its average acceleration?

Solution1. A = Final Velocity – Initial Velocity

Time2. A = 22m/s – 4 m/s =

3 s3 and 4. A = 6 m/ s2