/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 16 A \(1.50 \mathrm{~kg}\) book is ... [FREE SOLUTION] | 91Ó°ÊÓ

91Ó°ÊÓ

A \(1.50 \mathrm{~kg}\) book is sliding along a rough horizontal surface. cats, have a mass of about \(70 \mathrm{~kg}\) and have been clocked to run at up to \(72 \mathrm{mi} / \mathrm{h}(32 \mathrm{~m} / \mathrm{s}) .\) (a) How many joules of kinetic energy does such a swift cheetah have? (b) By what factor would its kinetic energy change \text { if its speed were doubled? }

Short Answer

Expert verified
The kinetic energy of the cheetah running at \(32 \mathrm{m/s}\) is \(35840 \mathrm{J}\). If the speed is doubled, the kinetic energy would be \(143360 \mathrm{J}\), or four times larger.

Step by step solution

01

Calculate Initial Kinetic Energy

First, calculate the initial kinetic energy of the cheetah using the formula for kinetic energy. The mass of the cheetah, \(m\), is given as \(70 \mathrm{kg}\) and the speed, \(v\), is given as \(32 \mathrm{m/s}\). Substitute these values into the formula to get \(KE = 0.5 \times 70 \times 32^2\)
02

Calculate Final Kinetic Energy

Next, calculate the final kinetic energy of the cheetah if its speed were doubled. This means \(v = 2 \times 32 = 64 \mathrm{m/s}\). Substitute these values into the formula to get \(KE = 0.5 \times 70 \times 64^2\)
03

Find the Factor of Change

Finally, to find the factor by which the kinetic energy changes if the speed is doubled, divide the final kinetic energy by the initial kinetic energy. This will give you the factor by which the kinetic energy changes if the speed is doubled.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91Ó°ÊÓ!

Key Concepts

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

Physics Problems
In the realm of physics, problems are designed to apply theoretical concepts to practical, real-world scenarios. This offers students a way to understand how abstract formulas and principles have direct implications on everyday phenomena. For instance, calculating the kinetic energy of a cheetah in motion translates the concept of energy into a tangible example. Kinetic energy, defined as the energy an object possesses due to its motion, is given by the formula:
\[ KE = \frac{1}{2} m v^2 \]
where \( m \) represents the object's mass and \( v \) is the velocity. By providing students with the mass and speed, they can use this formula to compute the kinetic energy. Such problems encourage students to become fluent in manipulating equations and understanding the variables involved, with the end goal of developing strong problem-solving skills.
Energy Conservation
Energy conservation is a fundamental concept in physics that dictates that within a closed system, the total energy remains constant—it can neither be created nor destroyed, but only transformed from one form to another. This principle helps us understand how energy flows within a system, and how it contributes to the system's behavior. In the cheetah's case, the kinetic energy calculated is part of the total mechanical energy it possesses. When discussing energy conservation in physics problems, it's essential to consider all forms of energy that might be in play, including potential energy, thermal energy, and energy lost due to friction or air resistance. This helps to provide a comprehensive understanding of the energy dynamics within a given system.
Mechanical Energy
Mechanical energy refers to the sum of kinetic and potential energy in a physical system. This form of energy is crucial in understanding how objects move and interact with their surroundings. For a moving cheetah, mechanical energy primarily consists of kinetic energy due to its swift motion. In scenarios where elevation changes or elastic forces come into play, potential energy would also contribute to the system's mechanical energy. Understanding how to quantify mechanical energy provides insight into predicting the motion of objects and analyzing different states of physical systems, such as the cheetah's ability to increase its speed or the work required to halt its motion. Dissecting complex physical systems into their energy components allows students to adopt a methodical approach to solve dynamic physics problems.

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

A \(4.00 \mathrm{~kg}\) block of ice is placed against one end of a horizontal spring that is fixed at the other end, has force constant \(k=200 \mathrm{~N} / \mathrm{m}\) and is compressed \(0.025 \mathrm{~m}\). The spring is released and accelerates the block along a horizontal surface. Ignore friction and the mass of the spring. (a) Calculate the work done on the block by the spring during the motion of the block from its initial position to where the spring has returned to its uncompressed length. (b) What is the speed of the block after it leaves the spring?

A \(75.0 \mathrm{~kg}\) painter climbs a ladder that is \(2.75 \mathrm{~m}\) long and leans against a vertical wall. The ladder makes a \(30.0^{\circ}\) angle with the wall. (a) How much work does gravity do on the painter? (b) Does the answer to part (a) depend on whether the painter climbs at constant speed or accelerates up the ladder?

A spring of force constant \(300.0 \mathrm{~N} / \mathrm{m}\) and unstretched length \(0.240 \mathrm{~m}\) is stretched by two forces, pulling in opposite directions at opposite ends of the spring, that increase to \(15.0 \mathrm{~N}\). How long will the spring now be, and how much work was required to stretch it that distance?

A pump is required to lift \(800 \mathrm{~kg}\) of water (about 210 gallons) per minute from a well \(14.0 \mathrm{~m}\) deep and eject it with a speed of \(18.0 \mathrm{~m} / \mathrm{s}\). (a) How much work is done per minute in lifting the water? (b) How much work is done in giving the water the kinetic energy it has when ejected? (c) What must be the power output of the pump?

A \(2.50 \mathrm{~kg}\) textbook is forced against one end of a horizontal spring of negligible mass that is fixed at the other end and has force constant \(250 \mathrm{~N} / \mathrm{m}\), compressing the spring a distance of 0.250 m. When released, the textbook slides on a horizontal tabletop with coefficient of kinetic friction \(\mu_{\mathrm{k}}=0.30 .\) Use the work-energy theorem to find how far the textbook moves from its initial position before it comes to rest.

See all solutions

Recommended explanations on Physics Textbooks

View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.