close solutoin list

A. An object is dropped from a height of 20 feet off the ground. What is its velocity when it hits the ground? B. Instead of being dropped, the object is thrown down, such that when it is 20 feet off the ground, it already has an initial velocity of 20 ft/s straight down. What is its velocity when it hits the ground? C. What did you assume in answering parts A and B? Give at least three examples of objects for which your assumptions are very good, and at least one example of an object for which your assumptions would fail badly.

BuyFind

Fundamentals of Chemical Engineeri...

1st Edition
Kevin D. Dahm + 1 other
Publisher: Cengage Learning
ISBN: 9781111580704
BuyFind

Fundamentals of Chemical Engineeri...

1st Edition
Kevin D. Dahm + 1 other
Publisher: Cengage Learning
ISBN: 9781111580704

Solutions

Chapter
Section
Chapter 1.7, Problem 22P
Textbook Problem

A. An object is dropped from a height of 20 feet off the ground. What is its velocity when it hits the ground?

B. Instead of being dropped, the object is thrown down, such that when it is 20 feet off the ground, it already has an initial velocity of 20 ft/s straight down. What is its velocity when it hits the ground?

C. What did you assume in answering parts A and B? Give at least three examples of objects for which your assumptions are very good, and at least one example of an object for which your assumptions would fail badly.

Expert Solution

A)

Interpretation Introduction

Interpretation:

The velocity of dropped object when hits the ground

Concept introduction:

Law of conservation of energy:

  The energy can neither be created nor be destroyed but it changes from one form to another. Accordingly, the energy entering into the open system will be equivalent to the energy leaving out of the same system, thereby conserving energy.

ΔP.E=ΔK.EΔP.E+ΔK.E=0MgΔz+MΔv22=0(v22v12)2=g(z2z1)v22=v12+[2g(z2z1)]

Here, gravity is g, mass is M, velocity is v, initial height is z1, final height is z2, and difference in height is Δz.

Explanation of Solution

Given information:

The initial height of the object =20 ft

Acceleration due to gravity =32.2ft/s2

Calculate the velocity of an object hits the ground.

v22=v12+[2g(z2z1)]        (1)

Substitute 32.2ft/s2 for g, 20 ft for z1, 0 for v1 and 0 for z2 in equation (1)

Expert Solution

B)

Interpretation Introduction

Interpretation:

The velocity of thrown down object when hits the ground

Concept introduction:

Law of conservation of energy:

  The energy can neither be created nor be destroyed but it changes from one form to another. Accordingly, the energy entering into the open system will be equivalent to the energy leaving out of the same system, thereby conserving energy.

The law of energy conservation for the thrown ball

ΔP.E+ΔK.E=0MgΔz+MΔv22=0(v22v12)2=g(z2z1)v2=2g(z1z2)+v12

Expert Solution

C)

Interpretation Introduction

Interpretation:

Examples for the assumption made in part A and B have to be determined.

Concept introduction:

Air resistance is depending on the ratio of surface area to the mass, if the mass is less and the surface area is more means air resistance is more.

Want to see this answer and more?

Bartleby provides explanations to thousands of textbook problems written by our experts, many with advanced degrees!

See solution

Chapter 1 Solutions

Fundamentals of Chemical Engineering Thermodynamics (MindTap Course List)
Show all chapter solutions

Additional Engineering Textbook Solutions

Find more solutions based on key concepts
Show solutions
Describe the agile development process.

Fundamentals of Information Systems

What is a relationship, and what three types of relationships exist?

Database Systems: Design, Implementation, & Management

If the C.I.A. triad is incomplete, why is it so commonly used in security?

Principles of Information Security (MindTap Course List)

What is a telecommunications protocol?

Fundamentals of Information Systems

Estimate how much material is needed to make 100,000 traffic yield signs. Investigate the size of one side of a...

Engineering Fundamentals: An Introduction to Engineering (MindTap Course List)

_______ displays use organic molecules that are self-illuminating and, thus, do not require a backlight. (342) ...

Enhanced Discovering Computers 2017 (Shelly Cashman Series) (MindTap Course List)

What are the advantages of welded piping systems over other joining methods?

Welding: Principles and Applications (MindTap Course List)

If your motherboard supports ECC DDR3 memory, can you substitute non-ECC DDR3 memory?

A+ Guide to Hardware (Standalone Book) (MindTap Course List)