Question

As you are walking, you foot gets caught on an uneven piece of sidewalk and you trip and fall. Which of the following explains what is happening using Newton's Laws? (1 point)
Responses

Your foot pushes the sidewalk with such force that it causes the next piece of sidewalk to be uprooted, which makes your next step miss your footing
Your foot pushes the sidewalk with such force that it causes the next piece of sidewalk to be uprooted, which makes your next step miss your footing

Your foot hit the sidewalk and provided a force on it, so the sidewalk will provide another force back on your foot, equal in magnitude but opposite in direct
Your foot hit the sidewalk and provided a force on it, so the sidewalk will provide another force back on your foot, equal in magnitude but opposite in direct

The sidewalk provided a force to stop your foot, but the top of your body was still moving which is what causes you to tip over
The sidewalk provided a force to stop your foot, but the top of your body was still moving which is what causes you to tip over

The sidewalk pushed you, causing a rapid force that made you fall

Answer 1

"The sidewalk provided a force to stop your foot, but the top of your body was still moving which is what causes you to tip over."

Why: when your foot hits the uneven sidewalk it is abruptly stopped by the contact force from the ground (and the ground pushes back — Newton's 3rd law). Your upper body, however, keeps moving forward by inertia (Newton's 1st law). That forward motion about the stopped foot produces a torque that rotates your body forward, so you tip and fall.