Velocity• The speed and direction of an object’s

motion.–88 km / hr southwest

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VELOCITYSPEED IN A GIVEN

DIRECTION

Vd

t=

direction

A bird flies south at 20 m/s.

• SPEED = 20 m/s• VELOCITY = 20 m/s south

A tropical disturbance spotted east of the Philippines was moving at 60 km per hour at a Northwesterly direction and having maximum sustained winds of 150 km/h? What is the storm’s velocity?

Given: S= 60km/h T= 10s dir= NW

1.Formula V= d/t with dir

2.Work/Answer V= 60km/h NW

CONSTANT VELOCITY

CHANGING VELOCITY

COMBINING VELOCITIES

How fast will this ball move?

What factors may affect its speed?

COMBINING VELOCITIES

Rowing speed = 16 km/hr

River speed (downstream) = 10 km/hr

Combined velocity: 26 km/hr

V1(Boat) = 16 km/hr

V2 (river) = 10 km/hr

What is the velocity if you are moving upstream?

Combined velocity: (V1) 16 km/hr – (V2) 10 km/hr = (CV) 6 km/hr

Why is the idea of combining velocities important to launching rockets?

1. A runner moving eastward covers a distance of a 100 meters in 10 seconds. What is his velocity?

Given: D= 100 m T= 10s dir= East

1.Formula V= d/t with dir

2.Work V= 100m/10s East

3.Answer V= 10m/s East

3. Lisa is walking to a friend’s house. She walks 500m for 10 minutes, then realizes she forgot something important to bring. She turns around, and hurries back to her house. The walk/jog back takes her 5 minutes.

Given: Total D= 500m + 500m = 1,000m

Total T= 10min + 5 min= 15 min

D= 500m

D= 500m

T= 10 min

T= 5 min

3. Lisa is walking to a friend’s house. She walks 500m for 10 minutes, then realizes she forgot something important to bring. She turns around, and hurries back to her house. The walk/jog back takes her 5 minutes.

a. What was her average speed in m/min?

Given: Total D= 500m + 500m = 1,000m

Total T= 10min + 5 min= 15min

1.Formula Ave S = total D/total T

2.Work Ave S = 1,000m/15min

3.Answer Ave S = 67 m/min

4. Nelson is running around the track oval. The oval is 800m long. He is running at a constant speed. It takes him 180 s to complete the track and get back to where he started.

a. What is Nelson’s speed in m/s?

Given: d= 800 m t= 180 s running at constant speed

Given: d= 800 m t= 180 s running at constant speed

1. Formula S= d/t 2. Work V= 800m/180s around oval3. Answer V= 4.44 m/s around oval

a. What is Nelson’s speed in m/s?

If Nelson is running at constant speed, is he also moving at constant velocity ?

No, he is always changing direction

(running around the oval).

3. Nemo is swimming his way to his best friend’s house Crush (the turtle). Nemo is swimming at 12 km/h and the current is moving at 10 km/hr.

a. On the way to Crush’s house, he swims with the current. What is Nemo’s combined velocity on the way to Crush’s house?

Given: V1= 12km/h V2= 10 km/h dir= to Crush’s house

(Nemo) (current)

1.Formula CV= V1 + V22. Work CV= 12 km/h + 10 km/h3. Answer CV= 22 km/h to Crush’s house

Current

Nemo

b. When Nemo leaves Crush’s to go home, he has to swim against the current.

What is Nemo’s combined velocity on the way home?

Given: V1= 12km/h V2= 10 km/h dir= Nemo’s home

1.Formula CV= V1 - V22. Work CV= 12 km/h - 10 km/h3. Answer CV= 2 km/h on the way home