1. Physics 2015 – Mechanical Energy Conservation Department of Physics & Astronomy Minilab 6 Mechanical Energy Conservation Page 1

2. Physics 2015 – Mechanical Energy Conservation PURPOSE Study energy conservation by looking at the relationship between three different types of energy: Gravitational Potential Energy (GPE) Elastic Potential Energy (EPE) Kinetic Energy (KE) Department of Physics & AstronomyPage 2

3. Physics 2015 – Mechanical Energy Conservation THEORY Energy is conserved if we can add up all of the different types of energy acting in a closed system and see that the total sum is constant. A “closed system” is one where no energy is added to or taken away from the system (in our case, a system with negligible friction) The types of energy will change depending on the setup. Ours were listed on the previous slide. Department of Physics & AstronomyPage 3

4. Physics 2015 – Mechanical Energy Conservation THEORY Department of Physics & AstronomyPage 4

5. Physics 2015 – Mechanical Energy Conservation EQUIPMENT photogate Note as the cart is released, the quantity GPE + EPE + KE should stay the same. We will be able to measure all three at any two different points of the cart’s travel. Department of Physics & AstronomyPage 5

6. Physics 2015 – Mechanical Energy Conservation PROCEDURE mg slope = -k Department of Physics & AstronomyPage 6

7. Physics 2015 – Mechanical Energy Conservation PROCEDURE Activity 2 – Conservation of Energy First, decide where you want to make your GPE = 0. Note that a good choice will make your calculations much easier! Measure ALL of the masses, including the mass of the cart, since this will be needed for your calculations! Then, use your equations to calculate GPE, EPE, and KE for a cart without mass on the top, and for a cart with mass. Department of Physics & AstronomyPage 7

8. Physics 2015 – Mechanical Energy Conservation HINTS Department of Physics & AstronomyPage 8