a car is traveling at 36 km per hour speed upto 72 kilometre per hour in 5 seconds what is it's acceleration ?if the same car stops in 20 seconds ,what is the retardation?
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Intial Speed of Car(u)=36 km/h
36 km/h in m/s=36×5/18=10 m/s
Final Speed of Car(v)=72 km/h
72 km/h in m/s=72×5/18=20 m/s
Time(t)=5 seconds
Acceleration=a
Use Equation of Motion to Find Acceleration
v=u+at
20=10+5a
20-10=5a
10=5a
a=10/5
a=2
Acceleration=2 m/s²
In Case 2
Intial Velocity (u)=20 m/s
Final Velocity when Car Stop(v)=0 m/s
Time taken to stop(t)=20 s
Retardation (negative Acceleration)=r
Again use Equation of Motion
v=u+rt
0=20+20r
-20=20r
r=-20/20
r=-1
Retardation=-1 m/s²
Acceleration
It mean Rate of Change in Velocity.Like Here given Acceleration is 2m/s² means Every Second it's Velocity is increasing by 2m/s.
Acceleration=2 m/s²
Retardation=-1 m/s²
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