RK Patrol

1 / 15

# RK Patrol - PowerPoint PPT Presentation

RK Patrol. Mechanical Energy and its types: DISCOVERED What is meant by Conservation of Mechanical Energy: ANSWERED THINGS TO REMEMBER when solving conservation of Energy problems Formulas to be IMPLANTED on mind and EXAMPLES of Energy Transfers Problem SOLVED. The HOT, BURNING News TODAY:.

I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.

## PowerPoint Slideshow about 'RK Patrol' - varden

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.

- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript

### RK Patrol

Mechanical Energy and its types: DISCOVERED

What is meant by Conservation of Mechanical Energy: ANSWERED

THINGS TO REMEMBER when solving conservation of Energy problems

Formulas to be IMPLANTED on mind and EXAMPLES of Energy Transfers

Problem SOLVED

The HOT, BURNING News TODAY:

3 TYPES:

Kinetic Energy a.k.a. KE

Gravitational Potential Energy a.k.aPEg

Elastic Potential Energy a.k.a. PEs

Mechanical Energy and its types: DISCOVERED

In a closed system, nothing leaves and nothing enters. Therefore, in a closed system, total mechanical energy is conserved.

An example of a mechanical system: A satellite is orbiting the Earth only influenced by the conservative gravitational force and the mechanical energy is therefore conserved.

What is meant by Conservation of Mechanical Energy: ANSWERED

Carefully identify the system. Make sure it is closed; no objects can enter it or leave it. It must also be isolated; no external force can act on any object in the system. Thus, no work can be done on or by objects outside the system.

Is friction present? If it is, then the sum of kinetic and potential energy will not be constant. But, the sum of kinetic energy, potential energy and the work done against friction will be constant.

Finally, if there is no friction, find the initial and final total energies and set them equal

KEi + PEi = KEf + PEf

PE = mgh

KE = ½ mv2

KEi + PEi = KEf + PEf

PE = mgh

KE = ½ mv2

KEi + PEi = KEf + PEf

PE = mgh

KE = ½ mv2

KEi + PEi = KEf + PEf

PE = mgh

KE = ½ mv2

Problem:

A large chunk of ice with mass 15.0 kg falls from a roof 8.00 m above e the ground a. Find the kinetic energy of the ice when it reaches the ground b. What is the speed of the ice when it reaches the ground? c. Is the answer the same as you would determine by solving as a constant acceleration problem?

Problem SOLVED

Given: m = 15.0 kg

g = 9.80 m/s2

h = 8.00 m

KEi = 0

PEf= 0

Problem SOLVED

Unknowns: a. Kef b.Vf

Basic Equations: KEi + PEi = KEf + PEf

Solution:

KEi+ PEi = KEf + PEf

0 + mgh = KEf + 0

KEf = mgh = (15.0 kg) (9.80 m/s2) (8.00 m) = 1.18 x 10^3 J

b. KEf= ½ mvf2

vf2 = 2KEf = 2(1.18 x 10^3 J) =157 m2/s2

m 15.0 kg

vf = 12.5 m/s

c. yes

Problem SOLVED

I. IDENTIFICATION

1. What is mechanical energy?

2 – 4. Give the 3 types of Mechanical energy and their corresponding examples. (0.5 point each number)

5. What is meant by Conservation of Mechanical Energy?

6. A mechanical system has been mentioned earlier and in connection to that, cite an example of it.

7-9. Identify the formulas needed to be implanted on mind with regards to this topic.

10. What formula would perfectly suit to this problem and how is it derived?

Bill throws a 10 g ball straight down from a height of 2.0m. The ball strikes the floor at a speed of 7.5 m/s. What was the initial speed of the ball?