Answer:
cross out the false piece in blue and write the true piece in red
Answer:

Explanation:
Given:
- thickness of the base of the kettle,

- radius of the base of the kettle,

- temperature of the top surface of the kettle base,

- rate of heat transfer through the kettle to boil water,

- We have the latent heat vaporization of water,

- and thermal conductivity of aluminium,

<u>So, the heat rate:</u>


<u>From the Fourier's law of conduction we have:</u>


where:
area of the surface through which conduction occurs
temperature of the bottom surface

is the temperature of the bottom of the base surface of the kettle.
Answer:
Vr = 20 [km/h]
Explanation:
In order to solve this problem, we have to add the relative velocities. We must remember that velocity is a vector, therefore it has magnitude and direction. We will take the sea as the reference measurement level.
Let's take the direction of the ship as positive. Therefore the boy moves in the opposite direction (Negative) to the reference level (the sea).
![V_{r}=30-10\\V_{r}=20 [km/h]](https://tex.z-dn.net/?f=V_%7Br%7D%3D30-10%5C%5CV_%7Br%7D%3D20%20%5Bkm%2Fh%5D)
Answer:
v = 10 m/s
Explanation:
Given that,
Distance covered by a sprinter, d = 100 m
Time taken by him to reach the finish line, t = 10 s
We need to find his average velocity. We know that velocity is equal to the distance covered divided by time taken. So,
v = d/t

Hence, his average velocity is 10 m/s.
Answer:

Explanation:
<u>Elastic Potential Energy
</u>
Is the energy stored in an elastic material like a spring of constant k, in which case the energy is proportional to the square of the change of length Δx and the constant k.

Given a rubber band of a spring constant of k=5700 N/m that is holding potential energy of PE=8600 J, it's required to find the change of length under these conditions.
Solving for Δx:

Substituting:

Calculating:

