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2 years ago

1. Why is the acceleration in the example negative?

Physics

1 answer:

Reika [66]2 years ago

6 0

Answer:

Because the velocity v (As a Vector ) is going opposite direction ( -X axis ) .

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A barbel weighing 215N is raised to a height of 2.0 M above the ground. It is then dropped from that height.

aleksandrvk [35]

Answer:

430 J
6.26 m/s

Explanation:

A. The kinetic energy is the same as the initial potential energy:

PE = mgh = (215 N)(2.0 M) = 430 J

B. The velocity achieved by falling from a height h is given by ...

v = √(2gh)

v = √(2·9.8 m/s^2·2 m) = √(39.2 m^2/s^2)

v ≈ 6.26 m/s

8 0

3 years ago

Which model shows how a comet's tail changes during its orbit?

pentagon [3]

Third model shows how a comet's tail changes during its orbit...

mark brainliest

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2 years ago

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What is produced as the result of unequal warming of the earth's surface?

Soloha48 [4]

Unusual precipitation patterns

7 0

2 years ago

Many industries are powered via distant power stations. Calculate the current flowing through a 7,300m long 10. copper power lin

Oliga [24]

Answer:

Current, I = 1000 A

Explanation:

It is given that,

Length of the copper wire, l = 7300 m

Resistance of copper line, R = 10 ohms

Magnetic field, B = 0.1 T

$\mu_o=4\pi \times 10^{-7}\ T-m/A$

Resistivity, $\rho=1.72\times 10^{-8}\ \Omega-m$

We need to find the current flowing the copper wire. Firstly, we need to find the radius of he power line using physical dimensions as :

$R=\rho \dfrac{l}{A}$

$R=\rho \dfrac{l}{\pi r^2}$

$r=\sqrt{\dfrac{\rho l}{R\pi}}$

$r=\sqrt{\dfrac{1.72\times 10^{-8}\times 7300}{10\pi}}$

r = 0.00199 m

$r=1.99\times 10^{-3}\ m=2\times 10^{-3}\ m$

The magnetic field on a current carrying wire is given by :

$B=\dfrac{\mu_o I}{2\pi r}$

$I=\dfrac{2\pi rB}{\mu_o}$

$I=\dfrac{2\pi \times 0.1\times 2\times 10^{-3}}{4\pi \times 10^{-7}}$

I = 1000 A

So, the current of 1000 A is flowing through the copper wire. Hence, this is the required solution.

4 0

2 years ago

Suppose that you are headed toward a plateau 55 meters high. If the angle of elevation to the top of the plateau is 40degrees,

Iteru [2.4K]

Answer:

$x=65.55m$

Explanation:

Let x be the distance to the shore

From trigonometry properties:

$tan(40^{o} )=\frac{55m}{x} \\x=\frac{55m}{tan(40^{o} )} \\x=65.55m$

3 0

3 years ago