Answer:
8.79 J
Explanation:
Given that a slinky is traveling down the stairs, like in the video clip below. What is the total KINETIC ENERGY of the slinky at the bottom of the stairs (just before it stops moving) IF the Height of the stairs is 2 meters, the weight of the slinky is 4.41 Newtons, its spring constant is 0.84 N/m, and the distance the slinky is initially stretched (to get it going) is 0.25 meters??
Total energy = mgh
Total energy = 4.41 × 2 = 8.82 J
Elastic potential energy = 1/2 × Ke^2
Elastic potential energy = 1/2 × 0.84 × 0.25^2
Elastic potential energy = 0.02625
Also,
Total energy = P.E + K.E
Substitute them into the formula above
8.82 = 0.02625 + K.E
K.E = 8.82 - 0.02625
K.E = 8.79375
K.E = 8.79 J
Therefore, the KINETIC ENERGY of the slinky at the bottom of the stairs is 8.79 Joules approximately
Answer:
Explanation:
Reddening of sun's rays at sunset and sunrise is due to scattering of light . The white light consisting of seven colours coming from the sun are scattered in different directions when they fall on the air particles present in atmosphere . Red coloured light scatters least and it travels straight forward to the viewer on the earth . On the other hand other colours scatter most and therefore they go out of area of vision for the viewer on the earth . Since only red colour reaches the eye of the viewer , sun's ray appear red . This happens during sunrise and sunset . It is so because during this period , sun rays travel far greater distance through atmosphere , so scattering is most pronounced .
Answer: A
Explanation: The amount of work done by Joe is equal to the amount of work done by Bob, because both have the same weight, same bicycle, cycling the same road and started the same time but the average power exerted by Joe is greater than that of Bob because Joe climbed a mountain while Bob passed a lower grade road.
Answer:
- Option B) Absorbed energy results in the change in potential energy.
Explanation:
Please, find attached the graph that accompanies this question.
The<em> melting</em> proces is the change from solid phase to liquid phase. It is represented with the lower flat line with the symbol ΔHfus over it.
The line is flat because the temperature remains constant during this process. Thus, you know the option "C) As the temperature increases during melting, the kinetic energy also increases" is FALSE.
What happens during this process is:
- Most of the energy received by the particles from heating, during the melting process, goes to overcome the intermolecular bonds between the particles. This results in increasing the distance between the particles, so the internal potential energy increases. This is what the option <em>"B) Absorbed energy results in the change in potential energy" correctly describes.</em> Hence, option B) is TRUE.
Althoug most of the heat energy received is transformed into potential energy, yet a small part of the heat energy increases a bit the kinetic energy of the particles, because the particles will vibrate faster around their relatively fixed positions. Hence, the option "<em>A) The kinetic energy of the particles remains unchanged</em>" is FALSE.
As for option D) it is not reasonable at all: none chemical or physical priciple can be used to state that <em>the kinetic energy decreases as the particles move farther apart</em>. Thus, this is FALSE.