An electric device delivers a current of [tex]$15.0 A$[/tex] for 30 seconds. How many electrons flow through it?

Acceleration is the rate of change of velocity.
Negative acceleration occurs when the final velocity is less than the initial velocity.
An initial velocity faster than a final velocity implies decreasing velocity, hence negative acceleration.
Therefore, the answer is an initial velocity that is faster than a final velocity, resulting in ​

Explanation

Understanding the Problem We are asked to determine which scenario would most likely result in negative acceleration, given that the velocity is positive. Acceleration is defined as the rate of change of velocity with respect to time. Negative acceleration means the velocity is decreasing.

Analyzing the Options Let's analyze the options:



A final velocity that is faster than an initial velocity: This implies that the velocity is increasing, which means the acceleration is positive.
A time that is less than a half hour or A time that is greater than a half hour: The duration of time does not directly determine the sign of the acceleration. What matters is the change in velocity over that time.
An initial velocity that is faster than a final velocity: This implies that the velocity is decreasing, which means the acceleration is negative.


Applying the Acceleration Formula The formula for acceleration is: a = Δ t Δ v ​ = t f ​ − t i ​ v f ​ − v i ​ ​ Where: a = acceleration Δ v = change in velocity Δ t = change in time v f ​ = final velocity v i ​ = initial velocity t f ​ = final time t i ​ = initial time

Since the time interval ( t f ​ − t i ​ ) is always positive, the sign of the acceleration depends on the sign of the change in velocity ( v f ​ − v i ​ ). For negative acceleration, we need v f ​ − v i ​ < 0 , which means v f ​ < v i ​ . Therefore, an initial velocity that is faster than a final velocity would result in negative acceleration.

Conclusion Therefore, the most likely condition to yield a negative acceleration when the velocity is positive is when the initial velocity is faster than the final velocity.

Examples
Imagine you're driving a car. If you start slowing down (your initial velocity is higher than your final velocity), you're experiencing negative acceleration, also known as deceleration. This concept is crucial in physics for understanding motion and forces, and it applies to many real-world scenarios, from designing safer vehicles to understanding the movement of celestial bodies.

Answered by GinnyAnswer | 2025-07-08

The number of electrons that flow through the device delivering 15.0 A for 30 seconds is approximately 2.81 × 10²¹ electrons. This is calculated by finding the total charge flowing and then converting that charge to the number of electrons using the charge of a single electron. Therefore, the total charge of 450 C corresponds to about 2.81 × 10²¹ electrons.
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Answered by Anonymous | 2025-07-26