Kinetic Energy Questions - All Help Appreciated?

1.) If a system has zero momentum, does it necessarily have zero kinetic energy? What is an example to illustrate this answer?

2.) A sports car with a mass of 1200 kilograms travels down the road with a speed of 20 meters per second. Why cant we say that its momentum is smaller than its kinetic energy?

Thank You All!

1.) If a system has zero momentum, does it necessarily have zero kinetic energy? What is an example to illustrate this answer?

Momentum p = mv; so that v = p/m = 0/m = 0 when there is zero momentum p = 0. Therefore, KE = 1/2 mv^2 = 1/2 m0^2 = 0. Therefore, yes, if p = 0 then KE = 0 as well.

2.) A sports car with a mass of 1200 kilograms travels down the road with a speed of 20 meters per second. Why cant we say that its momentum is smaller than its kinetic energy?

Makes no sense, for one thing. That's comparing apples to oranges, momentum and KE are not the same thing. They don't have the same units of measure. p units are kg-m/sec^2 but kinetic energy is kg (m/sec)^2.

We could make the argument that momentum is embedded in kinetic energy. For example, KE = 1/2 mv^2 = 1/2 pv Thus, p, momentum, is just one factor in KE; so p < KE. But, and this is a big BUT, that's still comparing apples to oranges and not really meaningful.

Consumer Guide to Home Energy Savings $13.2 How efficient are front-load washing machines? When is it time to replace your old refrigerator? These questions and many more are answered in The Consumer Guide to Home Energy Savings.

Into the Cool $10.85 Scientists, theologians, and philosophers have all sought to answer the questions of why we are here and where we are going. Finding this natural basis of life has proved elusive, but in the eloquent and creative Into the Cool, Eric D....

Energy in Motion $4.9 Discusses potential and kinetic energy by using simple terminology and examples.

Pocket Guide to Crystals and Gemstones $7.91 Whether you are simply curious about the different types of stones and crystals or want to explore their uses, the POCKET GUIDE TO CRYSTALS AND GEMSTONES will answer your questions: What are they?What are their energy fields?Where can they be found?How...

Science Question of the Day (Paperback) $6.85 A collection of short questions cover such key topics as ecosystems, weather, energy, and animal adaptations.

---

Tags: Energy, energy equations chemistry, energy equations chennai, energy equations physics, energy equations spring, energy equations wavelength, energy equations wiki, energy questions and answers, energy questions for kids, environment, physics, science, technology