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3 years ago

8 Grade Science Explain how a Lava lamp demonstrates convection currents.

Physics

1 answer:

Greeley [361]3 years ago

5 0

Answer:

As a substance gains heat energy (in the case of the lava lamp, heat is transferred from the hot light bulb to the lava), it becomes less dense than the surrounding liquid ), causing the substance to rise.

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1. A truck with a mass of 8, 000 kg is traveling at 26.8 m/s when it hits the brakes. A.)What is the momentum of the truck befor

NikAS [45]

Answer:

1. A.) The moment of the truck before it hits the brakes is 214,400 kg·m/s

B.) The force it takes to stop the truck is approximately 17,290.4 N

Explanation:

1. A.) The given parameters are;

The mass of the truck, m = 8,000 kg

The velocity of the truck when it hits the brakes, u = 26.8 m/s

Momentum = Mass × Velocity

The moment of the truck = The mass of the truck × The velocity of the truck

Therefore;

The moment of the truck before it hits the brakes = 8,000 kg × 26.8 m/s = 214,400 kg·m/s

B.) The amount of momentum lost when the truck comes to a stop = The initial momentum of the truck

The time it takes the truck to come to a complete stop, t = 12.4 s

The deceleration, "a" of the truck is given by the following kinematic equation of motion

v = u - a·t

Where;

v = The final velocity of the truck = 0 m/s

u = The initial velocity = 26.8 m/s

a = the deceleration of the truck

t = The time of deceleration of the truck = 12.4 s

Substituting the known values gives;

0 = 26.8 - a × 12.4

Therefore;

26.8 = a × 12.4

a = 26.8/12.4 ≈ 2.1613

The deceleration (negative acceleration) of the truck, a ≈ 2.1613 m/s²

Force = Mass × Acceleration

The force required to stop the truck = The mass pf the truck × The deceleration (negative acceleration) given to the truck

∴ The force it takes to stop the truck = 8,000 kg × 2.1613 m/s² ≈ 17,290.4 N.

8 0

3 years ago

How long does it take light from a camera to travel to the face of someone standing 7 meters away?

mestny [16]

The time taken for the light to travel from the camera to someone standing 7 m away is 2.33×10¯⁸ s

Speed is simply defined as the distance travelled per unit time. Mathematically, it is expressed as:

<h3>Speed = distance / time </h3>

With the above formula, we can obtain the time taken for the light to travel from the camera to someone standing 7 m away. This can be obtained as follow:

Distance = 7 m

Speed of light = 3×10⁸ m/s

Time = Distance / speed

Time = 7 / 3×10⁸

Therefore, the time taken for the light to travel from the camera to someone standing 7 m away is 2.33×10¯⁸ s

Learn more: brainly.com/question/14988345

8 0

2 years ago

What is a catchy slogan to help people remember the difference between weathering and erosin

GaryK [48]

These are more of ideas to help your brain invent something less chessy...
Erosion is like corrosion, with no acid.
Erosion happens 'cuz the surface get frozen and beaten by the ocean. (they kinda rhyme) :)
Erosion is the transportation of, the deportation...
~OR~
I cant think of anything for weathering but i got something good, but its still cheesy/ ):

Erosions' got the grooves and so it moves. But weathering breakdown and changes so its molecules changes.
I'm sorry these kinda suck...

5 0

3 years ago

When a magnetic field is first turned on, the flux through a 20-turn loop varies with time according to Φm=5.0t2−2.0t, where Φm

goldfiish [28.3K]

Answer:

A) ( - 200t + 40 ) volts

B) b) anticlockwise , c) anticlockwise , d) clockwise , e) clockwise

Explanation:

Given data:

magnetic flux (Φm) = 5.0t^2 − 2.0t

number of turns = 20

<u>a) determine induced emf </u>

E = - N $\frac{d\beta }{dt}$

= - N ( 10t - 2 ) = - 20 ( 10t - 2 )

= - 200t + 40 volts

<u>b) Determine direction of induced current </u>

i) at t = 0

E = - 0 + 40 ( anticlockwise direction )

ii) at t = 0.10

E = -20 + 40 = 20 ( anticlockwise direction )

iii) at t = 1

E = - 200 + 40 = - 160 ( clockwise direction)

iv) at t = 2

E = -400 + 40 = - 360 ( clockwise direction )

8 0

3 years ago

Question 7

erastova [34]

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4 0

4 years ago

8 Grade Science Explain how a Lava lamp demonstrates convection currents. ​

8 Grade Science Explain how a Lava lamp demonstrates convection currents.