Show me your calculator.

Agenda for Tuesday Oct. 7th 1. Go over test2. Speed notes

**New grades posted**

MotionDef. – an objects change in position relative to a

reference point

• To observe motion you need a reference point/frame of reference– Observe an object in relation to a stationary object

• Describe direction of an object with a reference direction– North, south, east, west, up, down

Motion• Distance measures the path taken

• Displacement – change in position of an object– Must be a straight line (shorter than distance)– Must be in a particular direction

Q. Which should you use when calculating how much gas you will use on a trip?

Q. Which does the saying, “As the crow flies” refer to?

Start

End

15 m

6 m 6 m

Speed and Velocity

• An object is moving if it changes position against some background that stays the same

• Speed – how fast an object moves– Distance and time– UNITS = m/s– Equal distance in equal amounts of time =

constant speed

What is speed?

Agenda for Thursday Oct 9th 1. Finish notes2. Bozeman science3. Calculating speed

Average Speed

• Distance traveled divided by the total time

Speed = distance/time v=d/t

If you run 100 m in 10 seconds what is your average speed?

Velocity

• Velocity is speed and direction– 2.0 m/s north– 500 m/s toward California

• Direction can be positive or negative-4 -3 -2 -1 0 1 2 3 4

A little bit more about Velocity

If you are on a bus going 15 m/s east then you are traveling 15 m/s east.

While it is moving you stand up and walk down the bus’s aisle while it is moving.

Q: Are you still moving the same velocity as the bus?

15 m/s east

1 m/s east

15 m/s east + 1 m/s east = 16 m/s east

1 m/s west

15 m/s east

15 m/s east + (- 1 m/s west) = 14 m/s east

Calculating

If a person runs 30 meters in 10 seconds. What is their speed?

If a car travels at 150 km/h. How long would it take them to travel 350 km?

If you travel 120 km north in 3 hours, what is your velocity?

What is the difference between speed and velocity?

Agenda for Friday Oct 10th 1. Whiteboard questions2. Speed lab #2

1. What is the formula for speed?

2. What are the units for speed?

3. If I take the following path, what is the total distance traveled?

4. If I take the same path, what is my displacement?

10 m

10 m10 m

10 m

Start

End

5. What is the difference between speed and velocity?6. A football field is about 100 m long. If it takes a person 20 seconds to run its length, what is their average speed?

7. If you run at 12 m/s for 15 minutes, how far will you go?

8. What kind of graph displays the motion of an object over a period of time?

Speed Lab #2

After lab Do • Questions 1-3 on page 323• Questions 1-5 on page 324• Questions 1-2 on page 330

If you run at 12 m/s for 15 minutes, how far will you go?

Agenda for Monday Oct 13th 1. Moving Man

If the slope of a line on a “distance vs. time” graph is steep. What is

different about the motion compared to when it is not steep?

Agenda for Monday Oct 20th 1. Ramp Lab

Time 1 2 3 4 5 Ave

110

120

130

140

150

160

170

180

190

200

9. If the slope of a line on a “distance vs. time” graph is steep. What is different about the motion then when it is not steep?

10. Changing speed is called “acceleration” (speeding up) or deceleration (slowing down). Describe the shape of an acceleration line on a Distance vs. Time graph of acceleration.

Acceleration labMeasure distance every 10 cm.Measure time to reach the end.Do 5 trials at each increment (5 at 10 cm, 5 at 20 cm, etc)**BE VERY ACCURATE!**Data TableDistance Time 1 Time 2 Time 3 Time 4 Time 5 Ave.

10 cm20 cm30 cm

What is shown by a curved line on a distance vs time graph?

Agenda for Tuesday Feb 4th 1. Quiz2. Graph3. Acceleration notes

Graph

• Steeper the graph = faster motion• Horizontal line = stationary• Curved line = speed up or slowing down

Acceleration

• We know when our speed increases or decreases our velocity changes– Also when we change direction

• When you change velocity you are accelerating– Change in velocity is called acceleration– Acceleration includes direction as well– Units: m/s2

Acceleration as change in direction• Acceleration is a change in the direction

– WHY?

• Acceleration is a change in velocity– Velocity is speed AND direction

• If you are traveling at a constant speed and are turning in a circle, are you accelerating?

Calculating Acceleration

• Measure velocity at different times

Equation: acceleration = final velocity – initial velocity

timeOr

a = ∆v/t

Calculating Acceleration

• If acceleration is small, velocity is changing slowly• If acceleration is large, velocity is changing rapidly

• Positive acceleration means object is speeding up• Negative acceleration means object is slowing

down– Velocity is decreasing

Examplesa = ∆v/t

• If a person travels at 10 m/s and then speeds up to 15 m/s in 1.5 s, what is their acceleration?

• A person starts at 20 m/s and accelerates at 2 m/s2 until they reach 40 m/s. How long did they accelerate?

A skier was originally going 20 m/s and stopped in .5 s. What is the skier’s acceleration?

A flowerpot falls off a second story windowsill. The flowerpot starts from rest and hits the sidewalk 1.5 s later with a velocity of 14.7 m/s. What was the acceleration of the flowerpot?

What does ∆ stand for?Agenda for Thursday Feb 6th 1. Review Acceleration

1. Accel Problems

2. Motion Graphs1. Whiteboards2. Worksheet

Calculating Acceleration

A runner accelerates from 2 m/s to 6 m/s at a rate of 2 m/s2 . How long did it take?

A car is going 45 m/s and slows down to 24 m/s. It takes the car 5 s to slow down. What was the cars acceleration?

After a car accelerates at 5 m/s2 for 3 seconds it’s speed is 50 m/s. What was the initial velocity?

A person on a sled starts at the top of the hill standing still. They go down the hill and reach an acceleration of 3 m/s2 . It took 5 seconds to get to the bottom of the hill. What was the final velocity at the bottom of the hill?

A runner achieves a speed of 11 m/s after he starts. It took him 9 s to reach that speed. How long did it take? What distance did he cover?

Find the acceleration of a northbound subway train that slows down from 12 m/s to 9.6 m/s in .8 s.

WHITEBOARD QUESTIONS

Need a whiteboard, marker, paper towel, and calculator.

Match the following graphs to the descriptionsA. The car is stoppedB. Car is traveling at a constant speedC. Speed is decreasing

13

2

Match the part of the graph to the description4. Stationary5. Increasing speed6. Slow and constant speed7. Fast and constant speed8. Returning to start

9. A car accelerates from a standstill to 60 m/s in 10 s. What is the acceleration?

10. A cyclist accelerates from 5 m/s to 10 m/s in 5 s. What is the acceleration?

A person on a sled starts at the top of the hill standing still. They go down the hill and reach an

acceleration of 3 m/s2 . It took 5 seconds to get to the bottom of the hill. What was their change in velocity?

Agenda for Friday Feb 7th 1. Motion graphs

Test Thursday

1. Calculate the speed from 12s to 18s

2. Show me your homework.

Agenda for Monday Feb 10th 1. Finish motion Graphs2. Review Test Thursday

A cyclist accelerates from 5 m/s to 10 m/s in 5 s. What is the

acceleration?

Agenda for Tuesday Feb 11th 1. Library activity2. Review