In the example of a child being pulled on a sled, identify and describe the forces acting on the child-sled system. How does each force affect the motion of the system?

Answer 1

There are several forces acting on the child-sled system when the child is being pulled on a sled. These forces are:

1. Gravitational force: This force is the weight of the child and the sled pulling them downwards towards the Earth. It acts vertically downwards through the center of mass of the system. The gravitational force affects the motion by providing the system with a downward force, which gives it a tendency to stay on the surface and potentially cause friction.

2. Normal force: This force is exerted by the surface (e.g., ground or snow) on the child-sled system perpendicular to the surface. It acts upwards to counterbalance the weight of the system. The normal force helps the system maintain contact with the ground and provides stability.

3. Frictional force: This force arises due to the contact between the sled and the surface, opposing the motion of the sled. It acts parallel to the surface and opposite to the direction of motion. The frictional force affects the motion by providing resistance against the sled movement, making it harder to slide or reducing sliding speed.

4. Tension force: This force is exerted on the sled by the person pulling it. It acts in the direction of the pull and is responsible for accelerating the system. The tension force primarily affects the motion by providing a forward force, propelling the sled and the child.

These forces interact with each other to determine the overall motion of the child-sled system. The gravitational force and the normal force balance each other vertically, maintaining stability and ensuring contact with the ground. The frictional force opposes the motion, making it harder for the sled to slide or slowing it down, especially on surfaces with higher friction. The tension force is responsible for accelerating the system forward, providing the necessary force to overcome friction and make the sled move.