# What is Gravity? How is it a type of potential energy?

### QUESTION DESCRIPTION

**Assignment: SCI103 Phase 5 Lab Report**

**TITLE: Potential and Kinetic Energy**

**INSTRUCTIONS: Enter the Virtual Lab and conduct the experiments provided. Please type your answers on this form. When your lab report is complete, submit it to the Submitted Assignments area of the Virtual Classroom.**

**Part I – Answer the following questions while in the Phase 5 lab environment.**

Section 1 – From the left of the screen to the right, the **red balls** have a center of mass placed at 20 feet, 15 feet, and 10 feet high respectively.

- Suppose each red ball weighs 20 lbs. Find the potential energy
*(PE)*for each ball on each ramp. In this lab mass is given in pounds and height is in feet, so use**32.2 ft/sec**. Your answer will be in foot-pounds since US units are being used.PE = m g h where^{2}as the gravitational constant**g = 32.2 ft/sec**Ramp 1:Ramp 2:Ramp 3:^{2} - Predict the maximum speed (velocity) of each ball on each ramp. How would this speed change if each ball’s mass was doubled?
**ASSUMPTION:**assume there is no friction and that all the potential energy you calculated in question 1 is transformed into kinetic energy – PE = KE. Use the following equation.KE= ½ m v^{2 }You want to calculate v maximum speedv = [KE/ ½ m]^{½}This means divide the KE by half the mass and then take the square root.

Max v for 20 lb. ball | Max v for 40 lb. ball |

Ramp 1 | |

Ramp 2 | |

Ramp 3 |

Section 2 (Each of the green balls has a center of mass placed at 20 feet high). While each ramp looks identical, each ramp has a different amount of friction.

- Which ramp has the greatest friction?
- Suppose each green ball weighs 10 lbs. Assuming there is no friction, calculate the potential energy for each ball on each ramp.
- Again assuming there is no friction; predict the maximum speed of the ball on each ramp. On which ramp does the ball come closest to achieving this max speed?Use this table to organize your calculated values

PE | Max Seed (v) |

Ramp 1 | |

Ramp 2 | |

Ramp 3 |

**Part II – **For the following questions, provide your response in short answer format (2-3 sentences each). Use this Phase’s activities and resources to assist you in answering:

- What is Potential Energy
*(PE)*?**Give examples from the lab.** - What is Kinetic Energy
*(KE)*?**Give examples from the lab.** - What is Inertia?
- What is Gravity? How is it a type of potential energy?
- What is Mass and how does it affect energy?
- How do Potential and Kinetic energy (gravity and mechanical force) apply to the Law of Conservation of Energy?
- What is Friction? How does it affect energy use?