Question

A car travels with a uniform velocity of 20 m/s for 5 s. The brakes are then applied and the car is uniformly retarded and comes to rest in further 10 s. Find: (i) The distance which the car travels before the brakes are applied (ii) The retardation (iii) The distance travelled by the car after applying the brakes.​

Answer 1

Answer:

Retardation is obtained using the formula "v = u - a×t " , where v is final speed which is zero in this case,

u is initial speed , a is retardation and t is time

 

(1)  retardation a = u/t  = 25/10 = 2.5 m/s2 .

 

(2) distance travelled before applying break = 25×5 = 125 m

 

(3) distance S travelled after applying break is given by,  S = u×t - (1/2)×a×t2  = 25×10 - (1/2)×2.5×100 = 125 m

Step-by-step explanation:

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