Question

penny balance📝 enter your answer.what happens when the forces on an object suddenly change? follow your teachers instructions and set up the activity. identify the forces acting on the penny, before and after the forces suddenly change. record your observations of the pennys motion. be sure to ask your teacher for clarification as needed.now check out the video that was fast to see the phenomenon you modeled in the activity happening in real life.

Explanation:

When forces on an object (like a penny) suddenly change, the object's velocity (speed or direction of motion) changes, as described by Newton's first and second laws of motion. For a penny on a balance:

1. Before force change: The penny is at rest, with balanced forces: gravitational force (weight, downward: $F_g = mg$) and normal force from the balance (upward: $F_N$), so $F_g = F_N$, net force $F_{net}=0$.
2. After sudden force change: If the balance is moved quickly (e.g., accelerated upward), the normal force increases, creating an upward net force. This causes the penny to accelerate upward relative to its initial state; if the balance is accelerated downward quickly, the normal force decreases, and the penny may appear to "float" or accelerate downward faster than the balance. In the classic penny balance demo, a quick downward jerk of the balance removes the normal force temporarily, so gravity is the only acting force, making the penny fall freely while the balance moves down faster, causing the penny to lift off the balance briefly.

Answer:

When the forces on an object suddenly change, the object's motion (speed or direction) changes due to a non-zero net force. For the penny balance activity:

• Before force change: The penny is stationary, with upward normal force from the balance equal to the downward gravitational force (net force = 0).
• After sudden force change (e.g., quick downward jerk of the balance): The normal force is removed or reduced. Gravity becomes the only unbalanced force, so the penny accelerates downward (falls freely) while the balance moves down faster, causing the penny to lift off the balance temporarily.