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2 years ago

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

Physics

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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How do I calculate the tension in the horizontal string?

matrenka [14]

ANSWER

T₂ = 10.19N

EXPLANATION

Given:

• The mass of the ball, m = 1.8kg

First, we draw the forces acting on the ball, adding the vertical and horizontal components of each one,

In this position, the ball is at rest, so, by Newton's second law of motion, for each direction we have,

$\begin{gathered} T_{1y}-F_g=0_{}_{}_{} \\ T_2-T_{1x}=0 \end{gathered}$

The components of the tension of the first string can be found considering that they form a right triangle, where the vector of the tension is the hypotenuse,

$\begin{gathered} T_{1y}=T_1\cdot\cos 30\degree \\ T_{1x}=T_1\cdot\sin 30\degree \end{gathered}$

We have to find the tension in the horizontal string, T₂, but first, we have to find the tension 1 using the first equation,

$T_1\cos 30\degree-m\cdot g=0$

Solve for T₁,

$T_1=\frac{m\cdot g}{\cos30\degree}=\frac{1.8kg\cdot9.8m/s^2}{\cos 30\degree}\approx20.37N$

Now, we use the second equation to find the tension in the horizontal string,

$T_2-T_1\sin 30\degree=0$

Solve for T₂,

$T_2=T_1\sin 30\degree=20.37N\cdot\sin 30\degree\approx10.19N$

Hence, the tension in the horizontal string is 10.19N, rounded to the nearest hundredth.

8 0

1 year ago

A thin walled spherical shell is rolling on a surface. What

ExtremeBDS [4]

Answer:

$=\frac{1/3}{5/6} = 0.4$

Explanation:

Moment of inertia of given shell $= \frac{2}{3} MR^2$

where

M represent sphere mass

R -sphere radius

we know linear speed is given as $v = r\omega$

translational $K.E = \frac{1}{2} mv^2 = \frac{1}{2} m(r\omega)^2$

rotational $K.E = \frac{1}{2} I \omega^2 = \frac{1}{2} \frac{2}{3} MR^2 \omega^2$

total kinetic energy will be

$K.E = \frac{1}{2} m(r\omega)^2 + \frac{1}{2} \frac{2}{3} MR^2 \omega^2$

$K.E =\frac{5}{6} MR^2 \omega^2$

fraction of rotaional to total K.E

$=\frac{1/3}{5/6} = 0.4$

8 0

3 years ago

How does Sonar work?i will mark brainliest pls help

Fittoniya [83]

I don't like the wording of any of the choices on the list.

SONAR generates a short pulse of sound, like a 'peep' or a 'ping',
focused in one direction. If there's a solid object in that direction,
then some of the sound that hits it gets reflected back, toward the
source. The source listens to hear if any of the sound that it sent
out returns to it. If it hears its own 'ping' come back, it measures
the time it took for the sound to go out and come back. That tells
the SONAR equipment that there IS a solid object in that direction,
and also HOW FAR away it is.

RADAR works exactly the same way, except RADAR uses radio waves.

5 0

3 years ago

Reflection of the images example

NISA [10]

Answer:

reflection of water ,sound and water waves etc

8 0

3 years ago

Two double bonds means that the total number of electrons being shared in the molecule is

torisob [31]

One double bond consists 4 electrons, so 2 double bonds means 8 electrons

7 0

3 years ago