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.

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.

it about 600 mph from what i calculated

force is mass*acceleration.

we have a very small mass: 11.4*0.001 kg

if we want 0.035n of force, we need an acceleration:

0.035 = 11.4*0.001*a

a = 0.035/(11.4*0.001) m/s^2