Okay, let's break this down step-by-step:
* There is a force of 100N acting on the body.
* The mass of the body is 20kg.
* The body accelerates from rest to a velocity of 20ms^-1.
To calculate the distance over which this force acts:
1) Calculate the acceleration: Force / Mass = 100N / 20kg = 5ms^-2
2) Calculate the displacement (distance traveled) using: displacement = 1/2 * acceleration * time^2
Since the acceleration is constant, we can set the initial velocity to 0 and final velocity to 20ms^-1.
Then: time = (20ms^-1) / 5ms^-2 = 4s
3) Displacement = 1/2 * 5ms^-2 * 4s^2 = 20m
Therefore, the force of 100N acts on the body over a distance of 20m to accelerate it from rest to 20ms^-1.
Let me know if you have any other questions!