A2kg object is moving horizontally with a speed of 4 m/s. how much net force is required to keep the object moving at this speed and in this direction

F = 0, if you apply a force, the velocity of the object may change.

Explanation: If there is no force of friction or something like that, there is no actual force applied to the object, because it has not any acceleration. This means that the object reached an uniform motion state, this means that the object will move with the constant velocity until a force is applied over it. This is because if there is no force applied, there is no acceleration (by the second Newton's law, we have that F = m*a) and the acceleration is the rate of change of the velocity, so if there is no acceleration, there is no change in the velocity.

This means that the net force required to keep the object moving at 4m/s and un the same direction is zero; F = 0

adding a(n) to an electric circuit would increase the magnetic field around a wire;

b. solenoid

a solenoid is a type of electromagnet whose purpose is to generate a controlled magnetic field.

if the purpose of the solenoid is instead to impede changes in the electric current, a solenoid can be more specifically classified as an inductor rather than an electromagnet.

+15-35=-20

going in opposite directions