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?
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.
The phenomenon you are observing is called the "inertia of motion." Here is a step-by-step explanation of why the disc falls straight down into the glass when the index card is quickly pulled away:
1. Inertia: Every object tends to resist changes in its state of motion. This property is known as inertia.
2. Resting on the index card: Initially, the metal disc is resting on the index card, which is placed on top of the glass.
3. No external forces acting: When the disc is at rest, there are no external forces acting on it horizontally, meaning there is no force pushing or pulling it from left to right.
4. Quick horizontal movement: When the index card is quickly pulled away horizontally, it imparts a horizontal force on the disc to overcome its inertia and start moving it.
5. Friction and air resistance: As the index card moves quickly, the friction between its surface and the disc, as well as the air resistance acting on the disc, is not significant enough to prevent it from moving.
6. Conservation of motion: According to Newton's laws of motion, once the disc starts moving, it tends to keep moving in a straight line at a constant velocity unless acted upon by an external force.
7. Traction with the glass: As the disc moves forward due to the horizontal force from the index card, it comes into contact with the glass.
8. No horizontal forces acting: At this point, when the disc is in contact with the glass, there are no external horizontal forces acting on it.
9. Vertical force of gravity: However, the force of gravity is still acting vertically downwards on the disc, which constantly pulls it downwards.
10. Falling into the glass: Since there are no horizontal forces acting on the disc and the force of gravity is acting vertically, the disc falls straight down into the glass.
In summary, when the index card is quickly pulled away, the disc continues to move horizontally due to its inertia. However, since there are no horizontal forces acting on it, gravity pulls it straight down into the glass.
The phenomenon you are referring to is called the "Inertia" or "Inertial Motion." When the index card is pulled away quickly and horizontally, the metal disk falls straight down into the glass due to the principle of inertia.
Inertia is a fundamental concept in physics that states an object at rest or in motion tends to stay in that state unless acted upon by an external force. It also suggests that the motion of an object is independent of its orientation or the direction it is placed in.
In this scenario, when the index card is pulled horizontally, the metal disk initially moves with the card due to the friction between them. However, once the card is removed, the disk is no longer in contact with any surface and is free to move independently. Because of its inertia, it continues to travel in the same horizontal direction with the same velocity it had when the card was pulled away.
Since there are no horizontal forces acting on the disk to alter its motion, it maintains its horizontal velocity. Meanwhile, gravity acts perpendicularly to the Earth's surface, causing the disk to accelerate downward. As a result, the disk falls straight down into the glass while maintaining its initial horizontal velocity.
So, the reason the disk falls straight down into the glass when the index card is quickly pulled away horizontally is due to the inertia of the disk and the absence of horizontal forces acting upon it.