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2 years ago

6

A child is sliding down a slide at the playground. is the mechanical energy conserved. why or why not.

2 answers:

aleksandrvk [35]2 years ago

6 0

C: the mechanical energy isn't conserved. Some energy was lost to friction.

Nikolay [14]2 years ago

6 0

Answer: The correct answer is C.

Explanation:

According to the law conservation of the mechanical energy, the total mechanical energy in a closed system remains constant in the absence of friction.

In the given problem, a child is sliding down a slide at the playground.

When a child is on the top of the slide then the he has more potential energy. When he starts slides down the slide then the kinetic energy starts increasing.

At the bottom of the slide, he has more kinetic energy.

But some energy is lost here due to friction. Hence, the mechanical energy is not conserved.

Therefore, the correct option is C.

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Can some answer 7 a and b please

pav-90 [236]

Answer:

a.After $15$ second Mr Comer's speed $=$ $1.7 m/s$

b.Distance travelled by Mr.Comer in $15$ seconds $=$ $18.75\ m$

Explanation:

a. Lets recall our first equation of motion $V_{f} =V_{i} + at$

Now we know that $V_{i} = 0.8m/s$ , $a = 0.06\ m/s^2$ and

$t = 15 \ sec$

Plugging the values we have.

$V_{f} =V_{i} + at$

$V_{f} =0.8 + 0.06 \times 15$

$V_{f} =0.8+ 0.9$

$V_{f} =1.7 m/s$

Then Mr.Comer's speed after $15$ sec $=$ $1.7ms^-1$

b.

Lets find the distance and recall our third equation of motion.

$V_{f} ^2-V{i}^2 = 2as$

So $s =$ distance covered.

Dividing both sides with 2a we have.

$\frac{V_{f} ^2-V{i}^2}{2a} = 2as$

Plugging the values.

$\frac{(1.7)^2-(0.8)^2}{2\times0.06} = 2as$

$s= 18.75\ m$

So Mr.Comer will travel a distance of $s= 18.75\ m$ .

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What are three examples of constructive forces

Olin [163]

The three main constructive forces are crustal deformation, volcanic eruptions, and deposition of sediment.

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2 years ago

Mixing baking soda with vinegar is an example of an oxidation-reduction

34kurt

Answer:

B. False

Explanation:

The reaction of baking soda and vinegar produces carbon dioxide gas. It is an example of precipitation reactions.

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2 years ago

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Gnoma [55]

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gregori [183]

The answer is A: can change

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