- Books Name
- Science Made Easy Science Book
- Publication
- Science Made Easy
- Course
- CBSE Class 9
- Subject
- Science
Acceleration - Acceleration is seen in non-uniform motion and it can be defined as the rate of change of velocity with time.
- Acceleration (a) = Change in velocity/Time = (v-u)/t
where, v = final velocity, u = initial velocity
- If v > u, then ‘a’ will be positive (+ve).
Retardation/Deceleration - Deceleration is seen in non-uniform motion during decrease in velocity with time. It has same definition as acceleration
- Deceleration (a') = Change in velocity/Time = (v-u)/t
- Here, v < u, ‘a’ = negative (-ve).
- It is a vector quantity.
- SI unit – m/s2 ( meter per second square)
Example 1: A car speed increases from 40 km/hr to 60 km/hr in 5 sec. Calculate the acceleration of car.
Example 2: A car travelling with a speed of 20 km/hr comes into rest in 0.5 hrs. What will be the valu of its retardation?
EXAMPLE 3 : If the velocity of the car reduced to 80 m/s from 120 m/s in 8 seconds on applying breaks . Calculate its acceleration.