a toy car initially moving with a uniform velocity of 18 km?h comes to a stop in 2s. Find the retardation of the car in S.I. units.

r=-a
a=-18 ?5/18?1/2
a=-2.5ms-?

Initial Velocity= 18km/h  18*1000/60*60
Final Velocity= 0
Time= 2s
Therefore, Retardation= 5-0/2m/s^-2= 2.5m/s^-2
So the retardation is 2.5m/s^-2

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