<span>We know the change of thermal energy is proportional to the specific heat of the matter, its mass and the change of temperatures, according the following formula:
Q = C*m*(Tf-Ti)
where:
Q is the heat added or removed (in joules, J)
C is the specific heat of the matter, in our case air 1,000 J/(Kg*C)
m is the mass, in our case 50 kg of air
Tf is final temperature
Ti is initial temperature
then:
Q = 1000 * 50 * (30-20) = 500,000 Joules
That means that 500,000 joules need to be added to increase temperature of the room 10 ÂşC (from 20 to 30 ÂşC)</span>
Animals like bats and whales use something called echolocation (sounds or echoes that travel to the other animal) these echoes can let one animal let another one know that danger is near or that food is nearby etc it's like a telephone line
Answer:
The answers to your questions are given below
Explanation:
22. The energy of an electromagnetic wave and it's frequency are related by the following equation:
E = hf
Where:
E => is the energy
h => is the Planck's constant
f => is the frequency
From the equation i.e E = hf, we can conclude that the energy of a wave is directly proportional to it's frequency. This implies that an increase in the frequency of the wave will lead to an increase in the energy of the wave and also, a decrease in the frequency will lead to a decrease in the energy of the wave.
23. Gamma ray and radio wave are both electromagnetic waves. All electromagnetic waves has a constant speed of 3×10⁸ m/s in space.
Thus, gamma ray and radio wave have the same speed in space.
Converting 209 km/hr to m/s:
209 km/hr = 58.0 m/s
Contact distance = 0.1 m
Using the equation of motion:
2as = v² - u², where initial velocity is 0
a = (58)² / (2 x 0.1)
a = 1.68 x 10⁴ m/s²
