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The acceleration due to gravity: From the time of Galileo, physicists have known that near the surface of the Earth, gravity imparts a constant acceleration of 32 feet per second per second. Explain how this shows that if air resistance is ignored, velocity for a falling object is a linear function of time.

Short Answer

Expert verified
The velocity is a linear function of time: \( v = 32t \).

Step by step solution

01

Understanding Constant Acceleration

The acceleration due to gravity is given as 32 feet per second squared. This means that every second, the velocity of a falling object increases by 32 feet per second. Since acceleration is constant, it indicates a regular increase in velocity.
02

Formula of Acceleration

Acceleration is the rate of change of velocity with respect to time and is defined by the formula: \[ a = \frac{\Delta v}{\Delta t} \] where \( a \) is acceleration, \( \Delta v \) is the change in velocity, and \( \Delta t \) is the change in time. Here, \( a = 32 \) feet/second².
03

Deriving Velocity from Acceleration

Since acceleration is constant, we can find the velocity by integrating the acceleration with respect to time. Assuming the initial velocity \( v_0 = 0 \) (the object starts from rest), the velocity \( v \) at any time \( t \) is given by:\[ v = \int a \, dt = \int 32 \, dt = 32t + C \] where \( C \) is the integration constant. Since the initial velocity \( v_0 = 0 \) when \( t = 0 \), \( C = 0 \). Thus, \( v = 32t \).
04

Conclusion: Linear Relationship

The derived equation \( v = 32t \) indicates that the velocity \( v \) is directly proportional to time \( t \), showing a linear relationship. This means for each second, the velocity increases by a constant value of 32 feet per second, and thus, the velocity is a linear function of time.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Constant Acceleration
When we talk about constant acceleration, we mean that an object's velocity changes at a steady rate over time. In simpler terms, no matter how long the time lasts or how far the object travels, the increase in speed from one second to the next remains the same.

For example, with gravity on Earth, an object falls under a constant acceleration of 32 feet per second squared. What this really means is that every single second, the velocity, or speed of the object, increases by 32 feet per second, consistently.

This constant acceleration makes it predictable. We can use the formula:
  • \[ a = \frac{\Delta v}{\Delta t} \]
This is to calculate how quickly the speed changes over a given time period, where \( a \) represents acceleration, and \( \Delta v \) and \( \Delta t \) are changes in velocity and time, respectively.

Remember, the constancy of acceleration is what makes calculations straightforward and helps predict outcomes in physics problems.
Velocity-Time Relationship
The velocity-time relationship arises from the consistent acceleration experienced by an object. Due to constant acceleration, the relationship between an object's velocity and time becomes linear. If you think of a line on a graph, this is similar to how velocity behaves over time.

Let's look at the equation derived from the solution:
\[ v = 32t \]
This equation tells us that the velocity \( v \) is directly proportional to time \( t \).
  • If time doubles, velocity also doubles.
  • Every extra second adds a constant velocity of 32 feet per second.
This proportionality is what makes the function linear. Imagine a straight line on a graph where the angle and steepness represent how fast the velocity increases over time. A steeper line would mean a faster increase in velocity.
Gravity
Gravity is a force that acts on all objects with mass, pulling them toward the center of the Earth. Although it might sound complex, it's what keeps our feet on the ground! Near Earth's surface, gravity gives all falling objects a consistent acceleration, unmatched by any other force, unless factors like air resistance come into play.

At 32 feet per second squared, gravity's acceleration influences velocity in a predictable manner without any interference, leading to a constant change in speed. This means that if air resistance is ignored, any object, whether a coin or a more massive boulder, falls faster and faster, gaining 32 feet per second every passing second.

Understanding gravity's impact helps us comprehend not only the physical motions on our planet but also key scientific principles, bridging simple observations with core physical laws. This consistent pull of gravity is the backbone of the velocity-time relationship for a free-falling object.

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Most popular questions from this chapter

Radioactive decay: The amount remaining \(A\), in grams, of a radioactive substance is a function of time \(t\), measured in days since the experiment began. The equation of change for \(A\) is $$ \frac{d A}{d t}=-0.05 A $$ a. What is the exponential growth rate for \(A\) ? b. If initially there are 3 grams of the substance, find a formula for \(A\). c. What is the half-life of this radioactive substance?

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