The picture shows a physics lab set up. Metal Disk Index Card Glass Why does the disc fall straight down into the glass when we quickly pull the index card away from the glass in a horizontal direction?

Answer 1

The disc falls straight down into the glass because of the principle of inertia. When the index card is pulled quickly away from the glass in a horizontal direction, there is a sudden change in the motion of the disc. However, the disc tends to resist changes in its state of motion, according to Newton's first law of motion.

As the index card is pulled away, the disc already possesses some horizontal velocity due to its initial position. Since there are no horizontal forces acting on the disc once the index card is removed, according to Newton's first law, the disc maintains its horizontal velocity.

Simultaneously, gravity acts vertically downward on the disc, pulling it straight down towards the ground. As there are no other forces acting on the disc in the horizontal direction, the disc falls straight down into the glass, unaffected by its initial horizontal velocity.