Question

s c.6.p.13.1
a hockey puck slides across smooth ice. a skater gives it a gentle push and then stops touching it. it keeps moving for a while and slowly slows down. which statement best explains this?
the initial push started the motion, and a small opposing force (friction) gradually slows it down.
the puck keeps moving because no forces act on it after the push.
gravity makes it speed up across the ice.
only contact forces can affect motion, so it should stop immediately.

Explanation:

According to Newton's first law, an object in motion stays in motion unless acted upon by an external force. Here, the initial push is the force that starts the motion. And friction is the external force that gradually slows it down as the ice is not completely friction - less. Gravity acts vertically and does not speed it up horizontally. Also, non - contact forces like gravity can affect motion and the puck doesn't stop immediately because of inertia and the presence of a small opposing frictional force.

Answer:

The initial push started the motion, and a small opposing force (friction) gradually slows it down.