Question

a car travelling at a speed of 54 km h brakes are applied so as to produce a uniform acceleration of - 0.5 m/s^2. find how far the car will go before it is brought to rest

Answer 1

Answer:

Car will travel 225 m before coming to rest .

Explanation:

→ initial velocity of Car , u = 54 km h⁻¹

  on converting to ms⁻¹

 initial velocity of Car , u = 15 ms⁻¹

→  acceleration produced on applying brakes , a = -0.5 ms⁻²

→  final velocity of Car , v = 0

   (because, Car is brought to rest)

◆ We need to find , How far the Car will go before it is brought to rest

so,

Using first equation of motion to calculate the time ( t ) for which Car travelled before stopping

→ v = u + a t

→ 0 = 15 + ( -0.5 ) t

→ t = -15 / -0.5

→ t = 30 s

Now,

Using second equation of motion to calculate the distance travelled ( s ) by Car before coming to rest

→ s = u t + 1/2 a t²

→ s = ( 15 ) × ( 30 ) + 1/2 (-0.5) (30)²

→ s = 450 + ( - 225 )

→ s = 450 - 225

→ s = 225 m

Therefore,

Car will travel 225 m before it is brought to rest .