Que1: When will you say that a body is in (i) uniform acceleration
(ii) non uniform acceleration
Ans: i) A body is said to be in uniform acceleration if its velocity increase or decrease with constant rate or same rate in a interval of time i. e. The rate of change of velocity is constant.
(ii) A body is said to be in non uniform acceleration if its velocity increases or decreases but not in constant rate in a interval of time.
That is the rate of change of velocity is not constant.
Que2: A bus decreases its speed from 80km/h to 60km/h in 5 sec. find its accerelation.
Ans2:
The accerelation = change in velocity /time
Given time = 5sec
Velocity initial (u) :
80*5/18= 22.22 m/s
Velocity final (v) :
60*5/18= 16.66m/s
Acceleration, a = v- u / time
=16.6-22.2/5
= -1.12 m/s²
The negative acceleration shows that the speed of car is decreasing.
Que3: A train starting from railway station and moving with uniform acceleration attains speed of 40km/h in 10minutes. Find its acceleration
Ans3: the initial velocity will be zero as train is starting from station ;
initial velocity (u)= 0
Final velocity (v) = 40*5/18 = 11.11m/s
Time = 10*60= 600 sec
Acceleration, a = v – u/time
= 11.11/ 600
= 0.0185 m / s²
