In this question, two forces are applied to a 1 kg body. One force of 3 N is applied along the x-axis and another force of 4 N is applied along the y-axis. We want to find the magnitude of the resultant acceleration.

To find the resultant acceleration, we can use Newton`s second law of motion, which states that F = ma, where F is the net force applied, m is the mass of the object, and a is the acceleration.

Here, we can calculate the net force applied along the x-axis by finding the x-component of the force applied along the y-axis. Since these forces are perpendicular to each other, their components are also perpendicular. So, the net force in the x-direction is 3 N.

Similarly, the net force applied along the y-axis can be calculated by finding the y-component of the force applied along the x-axis. The y-component of the force is 4 N.

Now, we can use Pythagoras theorem to find the magnitude of the resultant force. The magnitude of the resultant force is the square root of the sum of the squares of the x-component and the y-component of the forces.

Using the Pythagorean theorem, we have:

Resultant force = √(3^