On a resting load, weighing 1.5 kg for 2 minutes, a force of 17.7 N acted, directed vertically

On a resting load, weighing 1.5 kg for 2 minutes, a force of 17.7 N acted, directed vertically upward to find the work of force, neglecting the cost of time.

Data: m (mass at rest) = 1.5 kg; t (duration of action on the load of force) = 2 minutes (120 s); F (effective force) = 17.7 N.

Constants: g (acceleration due to gravity) = 9.8 m / s2.

1) Resultant force: Fr = F – Ft = F – m * g = 17.7 – 1.5 * 9.8 = 3 N.

2) Acceleration with which the load began to move up: a = Fр / m = 3 / 1.5 = 2 m / s2.

3) Work of the force applied to the load: A = F * S = F * 0.5 * a * t ^ 2 = 17.7 * 0.5 * 2 * 120 ^ 2 = 254 880 J ≈ 255 kJ.

Answer: The work force is 255 kJ.