A small acceleration tells you that the velocity is changing slowly. A large acceleration tells you that the
velocity is changing quickly.
Suppose the velocity of a car increases from 50 km/h to 80 km/h in 5 seconds What is the average
acceleration of the car?
First, find the change in velocity. The change in velocity is the difference between the ending velocity ()
and the beginning velocity (). Then divide this difference by the time () that has passed. Use this formula
to flad average acceleration (a):
31
in the example of the car, you can find that average acceleration of the car is 6 km/h per second. The car's
velocity increases by 6 km/h nach second.
a-80 kaub-50 km/h-6 kuths)
5s
Frame of Referance
If you are sitting still in your classroom, you probably don't think you are moving. Compared to the room,
you are in the same position. But Earth apins on its axis and also orbits the sun Astronauts right say that
you are moving very quickly!
Sun
fonava
10000
full of
gadh
Earth
Rugp
(ar)
All motion is relative, meaning it is measured compared to some object. Scientists call this a frame of
eference. A frame of reference is an object to which you choose to compare the motion of other objects.
Passengers inside a train are not moving relative to the train. The frame of reference of a person standing
outside the train is different. To that person, the passengers are moving at the same velocity as the train-
oth are moving very quickly.