An object travelling at a speed of 36 kmph comes to rest in a distance of 200 m after the brakes were applied. The retardation produced by the brakes is

To find the retardation (negative acceleration), we use the equation of motion:

v² = u² + 2as

Where:

• v = final velocity = 0 m/s (since the object comes to rest)
• u = initial velocity = 36 km/h = 36 × (1000/3600) = 10 m/s
• a = retardation (to be calculated)
• s = distance = 200 m

Rearranging the formula for a:

a = (v² - u²) / 2s

Substitute the values:

a = (0² - 10²) / (2 × 200)

a = -100 / 400

a = -0.25 m/s²

The negative sign indicates retardation.

Final Answer

The retardation produced by the brakes is calculated based on the initial velocity, distance, and the object coming to rest. Here, the retardation is 0.25 m/s².