230 likes | 373 Views
V E L O CITY AND A CC E L E RATI O N. VELOCITY. SPEED IN A GIVEN DIRECTION. d. V. =. t. direction. A bird flies south at 20 m/s. SPEED = 20 m/s VELOCITY = 20 m/s south. CONSTANT VELOCITY. CHANGING VELOCITY. COMBINING VELOCITIES. How fast will this ball move?
E N D
VELOCITY SPEED IN A GIVEN DIRECTION d V = t direction
A bird flies south at 20 m/s. • SPEED = 20 m/s • VELOCITY = 20 m/s south
COMBINING VELOCITIES How fast will this ball move? What factors may affect its speed?
COMBINING VELOCITIES Rowing speed (downstream) = 16 km/hr River speed = 10 km/hr
How fast are you moving downstream? The 2 velocities combine V1(Boat) = 16 km/hr V2 (river) = 10 km/hr Combined Velocity = 26 km/hr
What is the velocity if you are moving upstream? (V1) 16 km/hr – (V2) 10 km/hr = (CV) 6 km/hr
Why is the idea of combining velocities important to launching rockets?
SATELLITES Launch Speed less than 8000 m/s Projectile falls to Earth Launch Speed less than 8000 m/s Projectile falls to Earth Launch Speed greater than 8000 m/s Projectile orbits Earth - Elliptical Path Launch Speed equal to 8000 m/s Projectile orbits Earth - Circular Path
ACCELERATION • TELLS HOW FAST IT IS MOVING • SHOWS HOW FAST VELOCITY IS CHANGING • HAS DIRECTION SPEEDING UP SLOWING DOWN CHANGING DIRECTION
ACCELERATION Rate of change in velocity Final velocity – Original Velocity Time A= Change in velocity divided by the time during which this change occurs
A roller coaster’s velocity at the top of the hill is 10 m/s. Two seconds later it reaches the bottom of the hill with a velocity of 26 m/s. What is the acceleration of the roller coaster?
SOLUTION: Final Velocity – Original Velocity Time A= 26 m/s- 10 m/s 2 s 16 m/s 2 s A= A= A= 8 m/sec/sec
DECELERATION • decrease in velocity • negative acceleration • slows down
CIRCULAR MOTION • Velocity is continuously changing • Object is accelerating even with constantspeed.
A car accelerated from 0 m/sec to 30 m/sec in 10 sec. What was the rate of acceleration? 3 m/sec/sec
A roller coaster is moving at 25 m/sec at the bottom of a hill. Three sec. later it reaches the top of the next hill, moving at 10 m/sec. What is the deceleration of the roller coaster? - 5 m/sec/sec
A train accelerated from 5 km/hr to 55 km/hr in 0.5 hr. What was the rate of acceleration? 100 km/hr/hr