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2 years ago

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A ball weighing 10 kg rolls down a frictionless incline with a 50 degree angle to the horizontal. if the balls initial velocity

was 0 m/s, how much does the mechanical energy of the system change by the time the ball reaches its destination.
A. increases by 12%

B. increases by 58%

C. decreases by 12%

D. does not change

1 answer:

Marat540 [252]2 years ago

8 0

The answer is the third one

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A force of 15 newtons is used to push a box along the floor a distance of 3 meters. How much was done?

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Answer:

$45 J$

Explanation:

The equation for work is:

$Work=Force*Distance$

We can substitute the given values into the equation:

$Work=15N*3m\\Work=45Nm\\Work=45J$

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3 years ago

The current theory of the structure of the

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Answers:

a) $2.82(10)^{21} kg$

b) $1410 J$

c) $36.62 m/s$

Explanation:

<h3>a) Mass of the continent</h3>

Density $\rho$ is defined as a relation between mass $m$ and volume $V$ :

$\rho=\frac{m}{V}$ (1)

Where:

$\rho=2720 kg/m^{3}$ is the average density of the continent

$m$ is the mass of the continent

$V$ is the volume of the continent, which can be estimated is we assume it as a a slab of rock 5300 km on a side and 37 km deep:

$V=(length)(width)(depth)=(5300 km)(5300 km)(37 km)=1,030,330,000 km^{3} \frac{(1000 m)^{3}}{1 km^{3}}=1.03933(10)^{18} m^{3}$

Finding the mass:

$m=\rho V$ (2)

$m=(2720 kg/m^{3})(1.03933(10)^{18} m^{3})$ (3)

$m=2.82(10)^{21} kg$ (4) This is the mass of the continent

<h3>b) Kinetic energy of the continent</h3>

Kinetic energy $K$ is given by the following equation:

$K=\frac{1}{2}mv^{2}$ (5)

Where:

$m=2.82(10)^{21} kg$ is the mass of the continent

$v=4.8 \frac{cm}{year} \frac{1 m}{100 cm} \frac{1 year}{365 days} \frac{1 day}{24 hours} \frac{1 hour}{3600 s}=1(10)^{-9} m/s$ is the velocity of the continent

$K=\frac{1}{2}(2.82(10)^{21} kg)(1(10)^{-9} m/s)^{2}$ (6)

$K=1410 J$ (7) This is the kinetic energy of the continent

<h3>c) Speed of the jogger</h3>

If we have a jogger with mass $m=77 kg$ and the same kinetic energy as that of the continent $1413 J$ , we can find its velocity by isolating $v$ from (5):

$v=\sqrt{\frac{2 K}{m}}$ (6)

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3 years ago

A 0.350kg bead slides on a curved fritionless wire,

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Answer:

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3 years ago

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In this problem we have the electric field intensity E:

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q = 6.4 × $10 ^{-19}$ coulombs

We also have the distance d that the load moved in a direction parallel to the field 1.2 × $10^{-2}$ meters.

We know that the electric potential energy (PE) is:

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None of the options shown is correct.

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3 years ago