Under the influence of what force a body with a mass of 3 kg will move with an acceleration of 1.5 m / s2.

In accordance with Newton’s second law in the inertial frame of reference, the acceleration that a body acquires under the action of a force is directly proportional to the magnitude of this force and inversely proportional to its mass:

a = F / m.

Then the force acting on the body is equal to

F = m * a;

F = 3 * 1.5 = 4.5 N.