1. 1. Velocity of the body is the distance travelled in a given direction per unit time. In other words speed in a given direction tells the velocity of the body. Velocity is the vector quantity having both magnitude as well as direction. S.I unit of velocity is M/sec.
2. 2. VELOCITY V S t = V=Velocity S=Displacement =Vector quantity T=Time taken
3. 3. The velocity of the body can be changed in any one of the following 3 ways:- By changing speed of the body. By changing the direction of motion of the body. By changing both , speed and distance of motion. Velocity of the body is said to be non-uniform when it covers unequal distances in a particular directions on equal interval of time or direction of motion of body changes.
4. 4. When velocity of the body is changing at the uniform rate over the period of time then average velocity of the body for this body is arithmetic mean of initial and final velocity. = initial velocity + final velocity 2 Vav =U + V 2 Vav= average velocity U= initial velocity V= final velocity
5. 5. How fast will this ball move? What factors may affect its speed?
6. 6. 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
7. 7. What is the velocity if you are moving upstream? Combined velocity: (V1) 16 km/hr (V2) 10 km/hr = (CV) 6 km/hr
8. 8. 1. 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 storms velocity? Given: S= 60km/h T= 10 sec dir.= northwest 1. Formula= V= d/t with direction 2.Work/Answer= V= 60km/h Northwest
9. 9. 2. 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
10. 10. 3. Lisa is walking to a friends 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
11. 11. a. What was her average speed in m/min? Given: Total Distance= 500m + 500m = 1,000m Total Time= 10min + 5 min= 15min 1. FormulaAverage Speed = total D/total Time 2.Work= Average Speed = 1,000m/15min 3.Answer= Average Speed = 67 m/min
12. 12. 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 Nelsons speed in m/s? Given: d= 800 m t= 180 s running at constant speed
13. 13. Given: d= 800 m t= 180 s running at constant speed 1. Formula= Velocity= d/t 2. Work= V= 800m/180 sec around oval 3. Answer= V= 4.44 m/s around oval a. What is Nelsons 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).
14. 14. 5. Nemo is swimming his way to his best friends 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 Crushs house, he swims with the current. What is Nemos combined velocity on the way to Crushs house? Given: V1= 12km/h V2= 10 km/h direction= to Crushs house (Nemo) (current) 1.Formula = Combined velocity= V1 + V2 2. Work= CV= 12 km/h + 10 km/h 3. Answer = CV= 22 km/h to Crushs house Current Nem0
15. 15. b. When Nemo leaves Crushs to go home, he has to swim against the current. What is Nemos combined velocity on the way home? Given: V1= 12km/h V2= 10 km/h dir.= Nemos home 1.Formula = Combined velocity= V1 - V2 2. Work = CV= 12 km/h - 10 km/h 3. Answer = CV= 2 km/h on the way home Against current