Motion

Monroe

November 5, 2009

To make speed, distance or velocity calculations, one must have a reference point.

A reference point is an unmoving point of comparison.

Billy Brainless jumped from a moving car. The car1.was on a road2.had a speedometer that showed 40 kilometers per hour3.was nowhere near water, hay or other soft “cushoney” stuff4.nor Billy had any protective gear at all.

Billy landed, and was not hurt.

How did Billy escape injury?

Billy Brainless jumped into a car, driving next to him at the same speed.

The reference point of the car’s speedometer was the road

Billy Brainless jumped into a car, driving next to him at the same speed.

The reference point of Billy was the other car.

Speed ~ distance divided by time

Continents move in centimeters per year

Airplanes in kilometers per hour

American cars in miles per hour

Comets in miles per second

Bullets in feet per second

These are all measurements of speed

Average speed is over a longer period of time.

If Sam Swiftfoot can run 10 miles in 73 minutes, what is his average speed?

Average speed is over a longer period of time.

If Sam Swiftfoot can run 10 miles in 73 minutes, what is his average speed?

10 miles 60 minutes 8.22 miles

----------- x -------------- = ---------------

73 minutes 1 hour hour

Instantaneous Speed ~ is the speed during an instant of time. Look at your speedometer for a good idea.

There really is no such number as instantaneous speed, however, because one can always reduce time until it reaches zero, at which time the number becomes undefined. One cannot divide by zero.

Velocity ~ is the speed in GIVEN DIRECTION. This implies displacement instead of distance.

Velocity ~ is the speed in GIVEN DIRECTION. This implies displacement instead of distance.

Distance ~ is how far you move, along the face of the Earth, compared to a reference point.

Velocity ~ is the speed in GIVEN DIRECTION. This implies displacement instead of distance.

Distance ~ is how far you move, along the face of the Earth, compared to a reference point.

Displacement ~ is the distance between the starting point and the ending point of a movement.

A horse took 15 seconds to run around an oval track, that was 1/4 mile in length.

What is the total distance that he ran?

A horse took 15 seconds to run around an oval track, that was 1/4 mile in length.

What is his total displacement?

A horse took 15 seconds to run around an oval track, that was 1/4 mile in length.

What was his average speed?

A horse took 15 seconds to run around an oval track, that was 1/4 mile in length.

What was his average volocity?

Return Home (Displacement)

Return Home (Distance)

Distance or Displacement

Each square represents one kilometer

Each square represents one hour

1. Shelly socialite left home at 7:00 for school2. After ½ hour she had completed the 1 kilometer trip3. At 9:00 she left school to go to her internship. She took a

car, and made the