The resultant of the forces acting on the body is 20 N and is directed horizontally.

The resultant of the forces acting on the body is 20 N and is directed horizontally. The body moves so that its coordinate changes according to the law x = 5 + 3t + 2t. What work is done in this case in 5 s?

These tasks: F (resultant of all forces acting on the body under consideration; the force vector is directed horizontally) = 20 N; the law of change of the coordinate x = 5 + 3t + 2t ^ 2; t (duration of movement) = 5 s.

1) Determine the path that the body under consideration will cover in 5 s: S = x (5) – x (0) = 5 + 3 * 5 + 2 * 5 ^ 2 – 5 + 3 * 0 + 2 * 0 ^ 2 = 65 m.

2) We calculate the work done on the body under consideration: A = F * S = 20 * 65 = 1300 J (1.3 kJ).

Answer: In 5 seconds, work of 1.3 kJ is done.