Chapter 4, Problem 1Q

Why does a child in a wagon seem to fall backward when you give the wagon a sharp pull forward?

To determine

Reason for a child in a wagon seems to fall backward when you give the wagon a sharp pull forward.

Answer to Problem 1Q

Solution:

It’s due to inertia

Explanation of Solution

The force is applied only on the wagon, but not on the child. The wagon accelerates due to this applied force. The child remains at rest, relative to the ground but the wagon moves. While the wagon moves forward and the child remains at rest, the child will move backward relative to the wagon. The child has inertia so child’s state of motion will not change until an outside force acts.

The child tends to remain at rest according to Newton’s first law of motion unless an external unbalanced force acts on the child. As force is applied only to the wagon, not the child. This makes the wagon accelerates out from under the child, making it look like the child falls backward relative to the wagon.