The kinetic energy of an object at a given instant is given by the formula KE = 1/2 * m * v^2, where m is the mass of the object and v is its velocity.
In this scenario, the net force acting on the object decreases linearly throughout the displacement, as shown on the graph, and reaches zero at the end of the displacement. Therefore, the object's velocity at the instant the net force is zero is equal to its final velocity, which is the velocity of the object when it comes to rest.
Since the net force acting on the object is zero at this point, the work done by the net force is also zero. Therefore, the initial kinetic energy of the object is equal to its final kinetic energy, which is the kinetic energy of the object when it comes to rest.
Therefore, we can use the formula for kinetic energy to find the kinetic energy of the object at the instant the net force is zero:
KE = 1/2 * m * v^2
KE = 1/2 * (3.0 kg) * (0 m/s)^2
KE = 0 J
The kinetic energy of the object at the instant the net force is zero is 0 J. This means that the object has come to rest and all its kinetic energy has been transformed into other forms of energy like heat or sound.