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Spring Potential Energy: More Energy

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What do you See?
5/3/11 page 372

The group of students seems to be doing an experiment together. Three of the kids are sitting at the desk working on it. One kid is measuring the height of a spring. The girl is writing on the chalkboard the equations for GPE, KE, and SPE.

What do you Think? 5/3/11 page 372

A roller coaster gets to it highest point by getting pulled up by a chain. It costs more to lift a roller coaster full of people because the mass is greater so more energy and work are required.

Physics Talk
5/3/11 page 374

. Spring potential energy- the energy stored in a spring due to its compression or stretch . SPE=1/2kx^2 . GPE+KE+SPE=constant . mgh+1/2mv^2+1/2kx^2=constant

Checking Up
page 377 5/3/11

1. the SPE became KE which then became GPE 2. 2 J 3. 2 J 4. spring constant and compression

Investigate
5/4/11 page 372

Objective: Determine the launch velocity of a vertical Ball launcher.

Theory: The launcher gives the ball KE which is converted into GPE. Assuming energy conservation: KEi=GPEf

1/2mv^2=mgh Vi=(2gh)^1/2

The velocity of the ball can also be measured using a photogate. If the photogate method produces the same result when this would validate our method.

the ball is launched using the spring. The spe of the spring gives the ball KE. the KE in turn is converted into GPE. SPE-KE-GPE or SPE-GPE SPE=.5kx^2 x= distance the spring is compressed K= spring constant
 * Trial || mass of ball || heigh || velocity || width of ball (m) || time through gate || V using photograph || percent difference ||
 * 1 || 1 ball || 1.00 || 4.43 || .038 || .0074 || 5.14 || -13.81 ||
 * 2 || 1 ball + ni || .81 || 3.98 || .040 || .0092 || 4.35 || -8.5 ||
 * 3 || 1 ball + 2 n || .66 || 3.6 || .042 || .011 || 3.82 || -5.76 ||
 * 4 || 1 ball + 3n || .53 || 3.22 || .044 || .013 || 3.38 || -4.97 ||

K=f/x

objective: determine the spring constant of the launcher. x=1.5 cm=.015m h=.53m .5k(.015)^2=(.0174)(9.8)(.53) k=803 N/M


 * trial || x || m || h || k ||
 * 1 || .015 || .0024 || 1 || 209 ||
 * 2 || .015 || .0074 || .81 || 522 ||
 * 3 || .015 || .0014 || .66 || 655 ||

Physics To Go
page 380 5/6/11

2. starts with SPE then they are equal in the middle and at the top there is GPE 3. It would require more energy so they would increase 4. SPE to KE to GPE to KE 5. It will not have enough momentum to get over the second hill if it is bigger because it loses energy due to friction. 6. energy is lost because of air resistance and friction 7. 44,100 J 8a.58,800 8b. 58,800 8c. 15 m 9. The GPE is increasing because it is getting higher 10. They gain the same because they finish at the same height 11a. yes 11b. .0729 J 11c. .12 m 12a. 18 m