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2 years ago

Why does the evaporation of sweat cool down your skin?

2 answers:

6 0

So sweat helps cool you down two ways. First, it makes your skin feel cooler when it's wet. And when it evaporates it removes some heat. But sweat will only evaporatoin an environment where there isn't much water in the air.

Sergeu [11.5K]2 years ago

4 0

It removes the heat on your skin

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A new roller coaster contains a loop-the-loop in which the car and rider are completely upside down. If the radius of the loop i

Mila [183]

Answer:

11.4 m/s

Explanation:

The expression for the Centripetal acceleration is :

$a=\frac{v^2}{R}$

Where, a is the accleration

v is the velocity around circumference of circle

R is radius of circle

In the given question,

a = g = Acceleration due to gravity as the car is at top = $9.81\ m/s^2$

v = ?

R = 13.2 m

So,

$9.81=\frac{v^2}{13.2}$

$v^2=9.81\times {13.2}$

v = 11.4 m/s

8 0

3 years ago

A cylindrical tungsten filament 14.0 cmcm long with a diameter of 1.00 mmmm is to be used in a machine for which the temperature

Advocard [28]

Answer:

Resistivity ρ=1.12 x 10^-4 Ωm

Explanation:

ρ= RA/l, where R is resistance, A is cross sectional area and l is length

A=πr^2

Note Current is given R is proportion to temperature and inversely proportional to Current R=(20+273)/14*10^-2 =2000Ω

⇒ρ=R*πr^2/l all length in metre.

8 0

3 years ago

Complete the sentence to describe what a wave is and what it does. A wave is a disturbance that carries from one place to anothe

kozerog [31]

Answer:

Energy

A wave is a disturbance that carries energy from one place to another through matter and space.

Explanation:

A wave can be defined as a form of disturbance that carries energy from one place to another through matter and space.

The energy of wave depends on the frequency of the wave and the wavelength (lambda) of that particular wave.

Mathematically,

V = f × lambda

5 0

3 years ago

Read 2 more answers

A 30 g horizontal metal bar, 13 cm long, is free to slide up and down between two tall, vertical metal rods that are 13 cm apart

natita [175]

Answer:

Terminal speed, v = 6901.07 m/s

Explanation:

It is given that,

Mass of the horizontal bar, m = 30 g = 0.03 kg

Length of the bar, l = 13 cm = 0.13 m

Magnetic field, $B=5.5\times 10^{-2}\ T$

Resistance, R = 1.2 ohms

We need to find the terminal speed oat which the bar falls. When terminal speed is reached,

Force of gravity = magnetic force

$mg=ilB$ ..................(1)

i is the current flowing

l is the length of the rod

Due to the motion in rods, an emf is induced in the coil which is given by :

$E=Blv$ , v is the speed of the bar

$iR=Blv$

$i=\dfrac{Blv}{R}$

Equation (1) becomes,

$mg=\dfrac{B^2l^2v}{R}$

$v=\dfrac{mgR}{B^2l^2}$

$v=\dfrac{0.03\times 9.8\times 1.2}{(5.5\times 10^{-2})^2(0.13)^2}$

v = 6901.07 m/s

So, the terminal speed at which the bar falls is 6901.07 m/s. Hence, this is the required solution.

5 0

2 years ago

Drop a paper a piece of thermocol and a piece of plastic from a height of 10 to 15 feet not the time for each object to hit the

lisov135 [29]

Answer:

Explanation:

According to Newton's law of gravitation , all objects should take same time to fall from same height , but it does not happen when we see a paper , a thermocol and a plastic paper to fall .

It happens due to air resistance . In case of paper , this is most pronounced , so it falls slowest . In case of plastic paper , the resistance is least so it falls fastest .

If we squeeze the piece of paper to make a lump so that it does not remain flat , it will fall the fastest , because in this case the air resistance on it becomes the least .

4 0

2 years ago