<h2><u>Question</u> :</h2>
When an athlete perspires after running
- Evaporation occurs and helps to cool the body.
- Convection cools the body.
- The body absorbs cold from the surrounding air.
- Heat is conducted away from the body.
<h2><u>Answer</u> :</h2>
When an athlete perspires after running evaporation occurs and helps to cool the body.
Correct option is A.
<h2><u>Explanation</u> :</h2>
When an athlete perspires after running then sweat evaporates and we know that evaporation causes cooling as evaporation requires heat energy. The required heat energy is taken away by the molecules of sweat when they convert from liquid into gas, and this causes cooling on the surface of body. That's why it helps to cool the body.
Vi = 0m/s
A = 99m/
Vf = 445m/s
T = 4.5s
D = ?
D = Vi(t) + 1/2(a)(t²)
D = 0m/s ( 4.5s) + 1/2(99m/s²)(4.5s)²
D = 1002 m
D = 1 x 10³ m
Answer:
The magnitudes of the net magnetic fields at points A and B is 2.66 x T
Explanation:
Given information :
The current of each wires, I = 4.7 A
dH = 0.19 m
dV = 0.41 m
The magnetic of straight-current wire :
B= μI/2πr
where
B = magnetic field (T)
μ = 1.26 x (N/)
I = Current (A)
r = radius (m)
the magnetic field at points A and B is the same because both of wires have the same distance. Based on the right-hand rule, the net magnetic field of A and B is canceled each other (or substracted). Thus,
BH = μI/2πr
= (1.26 x )(4.7)/(2π)(0.19)
= 4.96 x T
BV = μI/2πr
= (1.26 x )(4.7)/(2π)(0.41)
= 2.3 x T
hence,
the net magnetic field = BH - BV
= 4.96 x - 2.3 x
= 2.66 x T
The two bols of ice creams are composed of vanilla the same subtances
molecular cloud <interstellar cloud <1 Msun protostar <1 Msun star <intercloud gas
Explanation:
<u>Molecular cloud-</u> They are a variety of interstellar cloud in which molecular hydrogen can sustain themselves. They have a very low temperature ranging from -440 to -370 degrees Fahrenheit or between<u> 10 to 50 Kelvin. </u>Owing to their extremely low temperature, they appear mostly dark when viewed through telescopes.
<u>Interstellar cloud-</u> They are a congregation of a large number of interstellar gases, dust and plasma in any galaxy or universe. They have varying temperature depending on their proximity to a star. E.g. Neutral hydrogen atom clouds have a temperature of around <u>just 100 Kelvin</u> while those in the near vicinity of a star have temperatures as high as 10,000 Kelvin.
<u>1 Msun star-</u> These stars have temperature anywhere between <u>5300 and 6000 Kelvin</u>. The main source of such high surface temperature is nuclear fusion process where elemental hydrogen molecules are fused to form helium molecules.
<u>1 Msun protostar-</u> protostar is rather a young star which is still in formation phase (i.e. gathering mass from the parent molecular cloud). They have temperature anywhere between <u>2000-3000</u> kelvin and are accompanied by dust usually.
<u>Intercloud gas- </u>These are the remainder gases that are spread throughout the interstellar space. This Intercloud gas is divided into warm intercloud medium and extremely hot coronal gas with temperatures comparing to Sun’s corona. Warm intercloud forms the dominant part of intercloud gas with a temperature around <u>8000 Kelvin</u>.