Question

Jessica's weight is 540 newtons. According to the Third Law, if the Earth pulls on Jessica with a force of 540 N, then Jessica pulls on the Earth with a force of 540 newtons that acts in the opposite direction. However, if Jessica stumbles while rollerblading, she will fall down to the ground. Explain why this happens.

Answer 1

Both forces are not acting on the same body, there is not balance

Step-by-step explanation:

Jessica weights 540 N. If the Earth pulls on Jessica with a force of 540 N, so, Jessica pulls on the Earth with the same force of 540 N in the opposite direction.

When Jessica stumbles while rollerblading, she will fall to the ground. We need to explain this fact. We have two forces of the same magnitude 540 N and opposite direction, normally they should be in balance. However, this is not the case because each force acts on different bodies. 540 N are acting on Jessica down direction and 540 N are acting on the Earth up direction. In this sense, as both forces are not acting on the same body, there is not balance. Due to it, Jessica will fall to the ground, the net force on Jessica is 540 N down direction.

Finally, we can mention that both forces are not acting on the same body, there is not balance

Answer 2

This is because the earth is way heavier than Jessica hence has a greater force of gravity applied on Jessica that Jessica applies to earth. The distance between the Earth and Jessica is also very short hence the force of gravity on Jessica towards earth is greater. According to Newton's laws that states; if an unbalanced force acts on an object, it will change the object's state of motion (the object will accelerate). The earth cause Jesica to ‘accelerate’ towards the ‘core’ when she stumbles.