acceleration mr. monroe october 30, 2007. acceleration ~ is the change in rate of volocity
TRANSCRIPT
Acceleration
Mr. Monroe
October 30, 2007
Acceleration ~ is the change in rate of volocity.
Acceleration ~ is the change in rate of volocity.
change in velocity
Acceleration = ----------------------------------------
time taken to change
Acceleration ~ is the change in rate of volocity.
change in velocity
Acceleration = ----------------------------------------
time taken to change
(Vf - Vi)
Acceleration = ----------------------------------------
t
Example with POSITIVE acceleration
Positive acceleration
Initial velocity = 0 km/hr
Final velocity = 80 km/hr
Time = 15 seconds
Example with POSITIVE acceleration
Positive acceleration
Initial velocity = 0 km/hr
Final velocity = 80 km/hr
Time = 15 seconds
(80 km/hr - 0 km/hr)
Acceleration = ----------------------------
15 seconds
Example with POSITIVE acceleration
Positive acceleration
Initial velocity = 0 km/hr
Final velocity = 80 km/hr
Time = 15 seconds
(80 km/hr - 0 km/hr)
Acceleration = ----------------------------
15 seconds
Acceleration = 5.33 km/hr/sec
Example with NEGATIVE acceleration
Negative acceleration
Initial velocity = 80 km/hr
Final velocity = 0 km/hr
Time = 15 seconds
(0 km/hr - 80 km/hr)
Acceleration = ----------------------------
15 seconds
Acceleration = -5.33 km/hr/sec
A plane hits a mountain at a speed of 400 meters per second, and it takes the plane 3 seconds to stop. What is the acceleration of the plane?
A plane hits a mountain at a speed of 400 meters per second, and it takes the plane 3 seconds to stop. What is the acceleration of the plane?
Vf = 0 m/sVi = 400 m/sT = 3 s
(0 m/s) – (400 m/s)------------------------ = - 133 m/s/s (Note that this is negative, hence the sign)
3 s
A car hits a tree going 60 miles per hour. It takes the occupant .1 seconds to stop. What is her acceleration?
A car hits a tree going 60 miles per hour. It takes the occupant .1 seconds to stop. What is her acceleration?
Vf = 0 miles/hourVi = 60 miles/hourT = .1 s
(0 miles/hour) – (60 miles/hour)----------------------------------------- = - 600 miles/hour/second (Note that this is negative) .1 s
This is probably not a survivable accident.
A car hits a tree going 60 miles per hour. It takes the occupant .5 seconds to stop, because she was wearing a seat belt. What is her acceleration?
A car hits a tree going 60 miles per hour. It takes the occupant .5 seconds to stop, because she was wearing a seat belt. What is her acceleration?
Vf = 0 miles/hourVi = 60 miles/hourT = .5 s
(0 miles/hour) – (60 miles/hour)---------------------------------------- = - 120 miles/hour/second .5 s
This is a very survivable accident.
End of first part of presentation.
A cross-country runner accelerates at a rate of 1 meter per second, per second. How fast will he be running in 5 minutes?
A cross-country runner accelerates at a rate of 1 meter per second, per second. How fast will he be running in 5 minutes? The cross-country runner must be Chuck Norris
1 m /s 5 minutes 60 seconds------- x -------------- x ------------------ = 300 m/s s 1 1 minute
Most airplanes could not go this fast
Brett’s car accelerates from 0 meters per second, to 5 meters per second in 2.3 seconds. What is its rate of acceleration? At that rate of acceleration, how fast will it be going in 6 hours?
Brett’s car accelerates from 0 meters per second, to 5 meters per second in 2.3 seconds. What is its rate of acceleration? At that rate, how fast will it be going in 6 hours?
Vf = 5 m/sVi = 0 m/sT = 2.3 s
(5 m/s) – (0 m/s)------------------------ = 2.2 m/s/s is the rate of acceleration 2.3 s
At that rate, how fast will it be going in 6 hours?
2.2 m/s 6 hours 60 min 60 seconds------------ x--------------- x -------------- x -------------- = 47,520 meters per second s 1 1 hour 1 min
At that speed, you would be getting around the world, at the equator, in about 14 minutes.