The body moving evenly passes 2.5 seconds in five seconds after which it begins to move uniformly

The body moving evenly passes 2.5 seconds in five seconds after which it begins to move uniformly and within 5 seconds it passes 150 cm. With what acceleration did the body begin to move?

Given: t1 (duration of uniform movement) = 5 s; S1 (first path) = 2.5 m; t2 (duration of accelerated movement) = 5 s; S2 (second path) = 150 cm (in SI S2 = 1.5 m).

1) Constant speed of the taken body on the first path (initial speed on the second path): V1 = S1 / t1 = 2.5 / 5 = 0.5 m / s.

2) Acceleration of the body on the second path: S2 = V1 * t2 + a * t2 ^ 2/2, whence a = (S2 – V1 * t2) * 2 / t2 ^ 2 = (1.5 – 0.5 * 5) * 2/5 ^ 2 = (1.5 – 2.5) * 2/25 = -0.08 m / s2.

Answer: Acceleration is -0.08 m / s2.