13 slides

Dividing total distance by total time calculates average speed.

If the whole trip totaled 30 miles and took 3 minutes to go the 30 miles…..then

(30 miles / 3 minutes) = 10 miles/minute

Average speed = total miles total time

If a car’s average speed is 20 mi/hr, how many miles would it go in 2 hours.

(20 mi/hr) = total miles 2 = 6 2 hours

3

20(2) = 40 miles

Average speed = total miles total time

30 mi/hr = 90 miles 2 = 6

total time 3

(90 mi) / (30 mi/hr) = 3 hr trip

Velocity is speed plus a direction.

50 mi/hr is speed of a car 50 mi/hr going North is the velocity of a

car.

Acceleration is a change in speed or a change in direction.

When you speed up = acceleration When you slow down = acceleration When you change direction =

acceleration

A carousel is an example of acceleration

Average Acceleration = vf – vi time

Vf = final velocityVi = initial velocity (what velocity it starts at)

Average Acceleration = vf – vi time

A motorcycle travels at 9 m/s. After 2 seconds, the motorcycle is traveling 12 m/s. What is the average acceleration?

Average Acceleration = 12 – 9 3 = 1.5 m/s

2 2

You are walking 4 m/s toward the back of a bus traveling 20 m/s forward. Relative to the street your velocity is?

---------------20 m/s 4 m/s

(20-4 )= +16 m/s

Kilometers = 1000 meters

1 meter = 100 cm and

1000 mm

1 cm = 10 mm

If it takes Karen 1 hour to drive 40 kilometers to her aunt’s house. What is the distance from Karen’s house to her aunt’s house expressed in meters?

• Scientific notation looks like this. (Positive number = Big number) (Negative number = Small number)

2 * 105 which means = 2000002 * 10-5 which means = .00002

1 * 103 which means = 1000 1 * 10-3 which means = .001

Race Number

Average Speed

1 120

2 130

3 130

4 160

What is the average speed of all the races?

120 +130+ 130+ 160 = 540

540 /4 = (135)

What is the mean of all the race?

Mean = Average speed

An instance is a brief moment in time.

In an instant you can have a car wreck. In an instant, you can lose your purse. In an instant, you can get in a fight.

• At an instant as you drive home, you may have to hit your brakes to avoid a skater or slow down for a yield sign. In that instant, you may be going 2 mi/hr, although your average speed for the entire trip was 60 mi/hr.

• When instantaneous speed never changes = you are going at a constant speed