work-Energy+problems



**Describe the difference between Kinetic Energy and Potential Energy. ** Kinetic Energy and Potential Energy are different because kinetic energy is when the energy is released like when a rollorcoaster is going down a hill. Potential **energy is when**
 * kinetic energy is about to be released, an example, when a rollorcoaster is at the top of the hill.**

-Chris C

**How does it relate to what we observed using the Xpult? ** When we were using the Xpult it had potential energy when we pulled it back. Potential energy changes into Kinetic energy when we let go of the catapult handle and the ping pong ball is flying through the air.

-Chris C

** Work is the force used to move an object some distance **

** W = F x d **

** Force needed to lift the box = 100 Newtons﻿﻿ **

** Distance needed to lift the box = 2 meters **

** 1) What work was needed to move the box 2 meters? ** ** ( Newtons•meters is considered a Joule) ** 100X2=200 Joules

** Mechanical Advantage = Ouput force/ ** ** Input force **

** 2) The board is 30 meters long. The fulcrum is 3 meters from the Boulder and 9 meters from the person applying the force. A person applies a force of 5 newtons and the boulder is 15 Newtons. **

** What is the mechanical advantage? ** 15 Newtons/5 Newtons=3;1 Newtons

** What is the work being done by the Machine? ** 3 metersX15 newtons=45 Joules

** What is the work being done by the person? ** 9 metersX5 newtons=45 Joules

** Compare the Work of the person and machine. ** They do the same amount of work.

** Explain scientifically why the job is easier for the person and harder for the machine. (even though the work is the same) ** It is harder for the machine because it exerts 3 times the amount of force as the person.

** ﻿ **

Remember, work is force X distance!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

** ﻿ **