Answer:
2633.7 s
Explanation:
From the question,
Heat lost by the water heater = Heat gained by the water
Applying,
P = cm(t₂-t₁)/t.................. Equation 1
Where P = power of the heat, c = specific heat capacity of water, m = mass of water, t₁ = initial temperature, t₂ = final temperature, t = time
make t the subject of the equation
t = cm(t₂-t₁)/P.............. Equation 2
From the question,
Given: c = 4190 J/kgK, P = 3.5 kW = 3500 W, m = 40 kg, t₁ = 20°C, t₂ = 75°C
Substitute these values into equation 2
t = 4190×40(75-20)/3500
t = 9218000/3500
t = 2633.7 s
Answer:
can exchange energy with its surroundings through heat and work transfer. In other words, work and heat are the forms that energy can be transferred across the system boundary.
Answer:
The torque is 0.31 Nm.
Explanation:
Electrical energy, E = 8400 J
time, t = 1 min
Angular speed, w = 2900 rpm = 303.53 rad/s
efficiency = 2/3 of input power
The toque is given by
Answer:
Explanation:
1. We can find the temperature of each star using the Wien's Law. This law is given by:
(1)
So, the temperature of the first and the second star will be:
Now the relation between the absolute luminosity and apparent brightness is given:
(2)
Where:
- L is the absolute luminosity
- l is the apparent brightness
- r is the distance from us in light years
Now, we know that two stars have the same apparent brightness, in other words l₁ = l₂
If we use the equation (2) we have:
So the relative distance between both stars will be:
(3)
The Boltzmann Law says, (4)
- σ is the Boltzmann constant
- A is the area
- T is the temperature
- L is the absolute luminosity
Let's put (4) in (3) for each star.
As we know both stars have the same size we can canceled out the areas.
I hope it helps!
Answer:
What is quantum physics? Put simply, it's the physics that explains how everything works: the best description we have of the nature of the particles that make up matter and the forces with which they interact. Quantum physics underlies how atoms work, and so why chemistry and biology work as they do.