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2 years ago

A student built a fire using coal. the coal started to burn. which statement best describes the energy changes that occurred.

2 answers:

5 0

ANSWER: B. The thermal energy stored in the coal changed to light energy and chemical energy.
.
EXPLANATION: thermal energy is already within the coal and because of the light from the fire, that's obviously light energy. And in the end, there is a chemical reaction after the coal burns to ash, and that is chemical energy! I hope this helps!☺️ Please give Brainliest!!

sergiy2304 [10]2 years ago

4 0

Answer:

98% sure the answer is A, as coal, when burning, releases thermal and light energy through the fire.

Explanation:

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Nutka1998 [239]

Mass of first car = Initial mass (Mi) = 2 kg
Initial velocity (Vi) = 2 m/s

Mass of both cars together = Final mass (Mf) = 2 + 3 kg = 5 kg
Final Velocity (Vf) = ?

Applying law of conservation of momentum,

Mi x Vi = Mf x Vf
2 x 2 = 5 x Vf
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2 years ago

An applied force varies with position according to F = k1 x n − k2, where n = 3, k1 = 3.6 N/m3 , and k2 = 76 N. How much work is

aniked [119]

Answer:

The work done is 205 kJ.

Explanation:

Hi there!

Work can be calculated using the following equation:

W = F · Δx

Where:

W = work

F = applied force

Δx = displacement

In this case, the force varies with the position, so we can divide the traveled distance in very small parts and calculate the work done over each part of the trajectory. Then, we have to sum all the works and we will obtain the work done from the initial position (xi) to the final position (xf). This is the same as saying:

W = ∫ F · dx

F = 3.6 N/m³ · x³ - 76 N

W = ∫ (3.6 x³ - 76)dx

W = 0.9 x⁴ - 76x

Evaluating from xi to xf:

W = 0.9 N/m³ (21.9 m)⁴ - 76 N · 21.9 m - 0.9 N/m³(5.41 m)⁴ + 76 N · 5.41 m

W = 205 kJ

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2 years ago

45 V =

Valentin [98]

Explanation:

https://educationalghana.news.blog/2021/08/09/geography-human-physical-and-practical-for-wassce-novdec-candidates/

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1 year ago

A uniformly charged sphere has a total charge of 300uc and a radius of 8cm. Find the electric field density at A point 16cm from

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E = kQ 

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k = 9 × 10^9Nm²C^-2

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h = 16 × 10^ -2m

then,

E = 9e9 * 300e^-6 

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It shortens so that the tips reach faster

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