Question

A car is moving with speed 30m.due to application of brakes it travels 30m before stopping.find it's acceleration

Answer 1

We have,

U=Initial speed of car=30m/s

V=Final speed of car=0m/s (As it comes to rest)

S=Distance travelled after application of brakes=30m.

a= acceleration of car= ?

From the 3rd equation of motion we have:-

v²=u²+2as

(0)²=(30)²+2(a)(30)

0=900+60(a)

-900=60(a)

-900/60= a

-15m/s²= a [negative sign shows that it is retarding force or acceleration is opposite to the direction of motion]

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