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N76 [4]
2 years ago
14

A heater marked 2000W/3000W is switched on for 4 hours. For the first hour it is on the highest setting and for the last 3 hours

it is on the lowest setting
1.1 How much energy does it transfer to the room in kWh (9kWh)
​
Physics
1 answer:
Leni [432]2 years ago
3 0

Answer:

9 kW-hr

Explanation:

3000 W  = 3 kW          for 1 hr =    <u>3 kW - hr </u>

2000 W  = 2 kW          for 3 hr =  <u> 6 kW -hr</u>

<u />

total power =  <u> 3 + 6 = 9 kW-hr</u>

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A ___ force is not path-dependent and does not change the overall mechanical energy of an object.​
finlep [7]

Answer:

conservative

Explanation:

Nonconservative force is the force that depends on a path, however conservative does not depend on a path and it is not associated with the potential energy. When the work is done by an unconservative force, mechanical energy is added or removed. Friction is the best example for a non-conservative force. When these non-conservative forces are acting, the mechanical energy changes but these are not preserved.

hope this helped!

6 0
3 years ago
Read 2 more answers
A student attaches a block to a vertical spring so that the block-spring system will oscillate if the block-spring system is rel
vodka [1.7K]

Answer:

Time period of the motion will remain the same while the amplitude of the motion will change

Explanation:

As we know that time period of oscillation of spring block system is given as

T= 2\pi\sqrt{\frac{M}{k}}

now we know that

M = mass of the object

k = spring constant

So here we know that the time period is independent of the gravity

while the maximum displacement of the spring from its mean position will depends on the gravity as

mg = kx

x = \frac{mg}{k}

so we can say that

Time period of the motion will remain the same while the amplitude of the motion will change

4 0
3 years ago
An atom in the ground state has a collision with an electron, then emits a photon with a wavelength of 1240 nm. What conclusion
anyanavicka [17]

Answer:

attached below is the free body diagram of the missing  illustration

Initial kinetic energy of the electron = 3 eV

Explanation:

The conclusion that can be drawn about the kinetic energy of the electron is

E_{e} = E_{3}  - E_{1}

E_{e} = initial kinetic energy of the electron

E_{1} = -4 eV

E_{3} = -1 eV

insert the values into the equation above

E_{e} = -1 -(-4)  eV

   = -1 + 4 = 3 eV

6 0
3 years ago
Experiments using "optical tweezers" measure the elasticity of individual DNA molecules. For small enough changes in length, the
GalinKa [24]

Answer:

Spring constant, k = 0.3 N/m

Explanation:

It is given that,

Force acting on DNA molecule, F=1.5\ nN=1.5\times 10^{-9}\ N

The molecule got stretched by 5 nm, x=5\times 10^{-9}\ m

Let k is the spring constant of that DNA molecule. It can be calculated using the Hooke's law. It says that the force acting on the spring is directly proportional to the distance as :

F=-kx

k=\dfrac{F}{x}

k=\dfrac{1.5\times 10^{-9}\ N}{5\times 10^{-9}\ m}

k = 0.3 N/m

So, the spring constant of the DNA molecule is 0.3 N/m. Hence, this is the required solution.

8 0
3 years ago
What are 2 ways that we can express to show our connection to our culture
garik1379 [7]

Answer:

Food, clothes, language, and belief

6 0
3 years ago
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