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4 years ago

Energy transfer by convection is usually restricted to what type of substance?

Physics

2 answers:

dedylja [7]4 years ago

5 0

Answer: The correct answer is fluids.

Explanation:

There are 3 modes of heat transfer that happens:

1. Conduction: In this type of heat transfer, heat is transferred when there is direct contact between the two object.

2. Convection: In this type of heat transfer, heat is transferred when there is a movement of fluid (liquid or gas).

3. Radiation: In this type of heat transfer, heat is transferred when there is direct transfer of energy through space.

Hence, convection is only restricted to fluids which are liquids and gases.

just olya [345]4 years ago

3 0

the anwser is d) fluids

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Do electromagnetic waves travel through a medium

vladimir1956 [14]

No, they actually travel through the vacuum of outer space, but it also requires the absence of a material sedium.

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4 years ago

a spotted lizard runs at 3m/s at top speed. a girl wants to catch the lizard to keep as a pet. where should the girl place her c

Ann [662]

The acceleration due to earth's gravity is -9.8 m/s [dn] I thought... I'm assuming this is a projectile motion question asking for the range.

Break each kinematic quantity into their x and y components.

x y

v₁ = 3 m/s 0

v₂ = 3 m/s ?

Δd = ? -1.5

Δt = ? ?

a = 0 -10 m/s²

So the variable we are trying to find is Δdx (x component of displacement). We need to use a kinematic equation to do so. However, we obviously don't have enough given to find Δdx. This means we need to find something first, something we can use. How about Δt? Δt can be applied to both the x and y components. We have enough information in the y component list to find Δt. We can use this formula and solve for Δt.

Δdy = v₁y ( Δt ) + 1/2 ( ay ) ( Δt )²

Δdy = 1/2 ( ay ) ( Δt )² <- the first term cancels out since v₁y = 0.

2Δdy = ay ( Δt )²

2Δdy / ay = ( Δt )²

√ 2Δdy / ay = Δt

√ 2(-1.5 m/s) / -9.8 m/s² = Δt

√ -3.0 m/s / -9.8 m/s² = Δt

√ 0.306122449 s² = Δt

0.5532833352 s = Δt

Now, we can use this newly found quantity to solve for Δdx using the x component values using the appropriate kinematic equation.

Δdx = ( v₁x + v₂x / 2) ( Δt )

Δdx = ( ( 3.0 m/s + 3.0 m/s ) / 2 ) ( 0.5532833352 s )

Δdx = ( 6.0 m/s / 2 ) ( 0.5532833352 s )

Δdx = ( 3.0 m / s )( 0.5532833352 s )

Δdx = 1.659850006 m

Therefore, the girl should place her cage 1.7 m away from the platform to catch the lizard.

This solution assumes that the acceleration due to gravity is -10 m/s² [dn] and not -9.8 m/s² [dn]. If you need -9.8 m/s² [dn], then just substitute it into my solution. This was a pain to type lol

6 0

4 years ago

If one charge is quadrupled, what happens to the force between charges?

cestrela7 [59]

The force between charges is proportional to the product of
the two charges. If just one of them is quadrupled, then their
product is also quadrupled, and so is the force between them.

The same identical argument applies to the gravitational force
between masses.

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3 years ago

A train traveling at 27.5 m/s accelerates to 42.4 m/s over 75.0 s. What is the displacement of the train in this time period

Sergio [31]

Answer:

2621.25 meters

Explanation:

First, write down what we are given.

Initial velocity = 27.5 m/s

Final velocity = 42.4 m/s

Time = 75 seconds

We need to look at the kinematic equations and determine which one will be best. In this case, we need an equation with distance. I am going to use $v_{f}^{2} = v_{i}^{2} +2ad$ , but you can also use the other equation, $x = v_{o}t+\frac{1}{2}at^{2}$

We need to find acceleration. To find it, we need to use the formula for acceleration: $a = \frac{v_{f}-v_{i}}{t}$ . Plugging in values, $a = \frac{42.4-27.5}{75} = .199\ m/s^{2}$

Next, plug in what we know into the kinematics equation and solve for distance. $42.4^{2} = 27.5^{2} + 2(.199)(d)\\d = 2621.25\ meters$

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3 years ago

What must a mechanical wave travel through

konstantin123 [22]

A mechanical wave always consists of wiggles in some kind of material stuff. The material stuff may be air, water, rock, wood, steel ... almost anything, as long as it's some material. In general, whatever the waves are moving through is called the "medium". If there isn't any, like the vacuum in space, then mechanical waves can't travel there. For example, sound can't travel in space ... not even an inch.

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3 years ago