Speed

What is a

SPEED?

Definition: the distance an object travels from some reference point per unit of time

How do you

calculate

SPEED?

to calculate speed, divide the distance by the time:

s = d/t

speed = distance time

other ways to write the same formula:

s = d t ) d t

s s = d ÷ t

How to calculate SPEED

Velocity & Acceleration

What is a

VELOCITY?

Definition: velocity is speed with direction velocity changes when either speed or direction changes

Velocity changes when either speed or direction changes

What is a

ACCELERATION?

Definition: the amount that velocity changes in speed or direction

How to calculate acceleration:

final velocity minus starting velocity, divided by time

Vfinal - Voriginal

timeA =

A car goes from 10 mph to 30 mph in 4 seconds. What was its acceleration?

Original velocity:

Final velocity:

Time:

10 mph30 mph

4 sec

30 mph – 10 mph

4 sec

20 mph

4 sec

5 mi/hr/sec

Vfinal - Voriginal

timeA =

A runner runs 10 m/sec, crosses the finish line, then takes 5 seconds to stop. What was her acceleration?

Original velocity:

Final velocity:

Time:

10 m/sec0 m/sec

5 sec

0 m/sec – 10 m/sec

5 sec

-10 m/sec

5 sec

-2 m/sec/sec

Vfinal - Voriginal

timeA =

An airplane flies at 472 km/hr. One hour later, it is still flying at the same speed. What is its acceleration?

Original velocity:

Final velocity:

Time:

472 km/hr472 km/hr

1 hour

472 km/hr – 472 km/hr

1 hour

0 km/hr

1 hr

0 km/hr/hr

VfinalVoriginal time

final velocity:

original velocity:

time:

5 m/sec

25 m/sec

2 sec

Vfinal- Voriginal

timeA =

25 m/sec - 5 m/sec

2 sec

20 m/sec

2 sec= = 10 m/sec/sec

10 m/sec/sec