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2 years ago

If you sit close to a campfire, the fire warms you. Describe how thermal energy is transferred from the fire to you.

Physics

2 answers:

White raven [17]2 years ago

7 0

Answer:

Explanation:

When you sit by a campfire, most of the heat you are receiving from the fire does not come from hot air. ... This radiation carries energy which is converted to heat when it hits another object and is absorbed. In contrast, conduction involves the direct movement of heat through an object.

myrzilka [38]2 years ago

6 0

Answer:

Explanation:

hope this helps u stay safe

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The figure shows a 100-kg block being released from rest from a height of 1.0 m. It then takes it 0.90 s to reach the floor. Wha

Anna007 [38]

Answer:

The mass of the another block is 60 kg.

Explanation:

Given that,

Mass of block M= 100 kg

Height = 1.0 m

Time = 0.90 s

Let the mass of the other block is m.

We need to calculate the acceleration of each block

Using equation of motion

$s=ut+\dfrac{1}{2}at^2$

Put the value into the formula

$1.0=0+\dfrac{1}{2}\times a\times(0.90)^2$

$a=\dfrac{2\times1.0}{(0.90)^2}$

$a=2.46\ m/s^2$

We need to calculate the mass of the other block

Using newton's second law

The net force of the block M

$Ma=Mg-T$

$T=Mg-Ma$ ....(I)

The net force of the block m

$ma=T-mg$

Put the value of T from equation (I)

$ma=Mg-Ma-mg$

$m(a+g)=M(g-a)$

$m=\dfrac{M(g-a)}{(a+g)}$

Put the value into the formula

$m=\dfrac{100(9.8-2.46)}{2.46+9.8}$

$m=59.8\ \approx60\ kg$

Hence, The mass of the another block is 60 kg.

8 0

2 years ago

a race car accelerates uniformly from 18.5 m/s to 46.1m/s in 2.47 seconds detrrmine the acceleration of the car and distance tra

LenaWriter [7]

Because acceleration is constant, the acceleration of the car at any time is the same as its average acceleration over the duration. So

$a=\dfrac{\Delta v}{\Delta t}=\dfrac{46.1\,\frac{\mathrm m}{\mathrm s}-18.5\,\frac{\mathrm m}{\mathrm s}}{2.47\,\mathrm s}=11.2\,\dfrac{\mathrm m}{\mathrm s^2}$

Now, we have that

${v_f}^2-{v_0}^2=2a\Delta x$

so we end up with a distance traveled of

$\left(46.1\,\dfrac{\mathrm m}{\mathrm s}\right)^2-\left(18.5\,\dfrac{\mathrm m}{\mathrm s}\right)^2=2\left(11.2\,\dfrac{\mathrm m}{\mathrm s^2}\right)\Delta x$

$\implies\Delta x=79.6\,\mathrm m$

6 0

3 years ago

A person in the back of a pick-up moving at 20 m/s relative to the Earth, throws a baseball with a speed of 15 m/s in a directio

Bumek [7]

Answer:

This is known as a Galilean transformation where

V' = V - U

Where the primed frame is the Earth frame and the unprimed frame is the frame moving with respect to the moving frame

V - speed of object in the unprimed frame

U - speed of primed frame with respect to the unprimed frame

Here we have:

V = -15 m/s speed of ball in the moving frame (the truck)

U = -20 m/s speed of primed (rest) frame with respect to moving frame

So V' = -15 - (-20) = 5 m/s

It may help if you draw a vector representing the moving frame and then add

a vector representing the speed of the ball in the moving frame.

3 0

3 years ago

The gas pressure inside a container decreases when

avanturin [10]

Answer:

When the volume increases or when the temperature decreases

Explanation:

The ideal gas equation states that:

$pV= nRT$

where

p is the gas pressure

V is the volume

n is the number of moles of gas

R is the gas constant

T is the gas temperature

Assuming that we have a fixed amount of gas, so n is constant, we can rewrite the equation as

$\frac{pV}{T}=const.$

which means the following:

- Pressure is inversely proportional to the volume: this means that the pressure decreases when the volume increases

- Pressure is directly proportional to the temperature: this means that the pressure decreases when the temperature decreases

8 0

3 years ago

The attraction of liquid particles for a solid surface is due to ____.

White raven [17]

This attraction occurs from adhesion, also known as adsorption <span />

6 0

2 years ago

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