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2 years ago

A soccer player kicks a ball with a speed of 30 m/s at an angle of 10. How long does the ball stay in the air?

1 answer:

4 0

"10" is not a very satisfying description of an angle.
I'll assume it's 10 degrees, and that it's the angle of the initial trajectory
above the horizontal.

The vertical component of the ball's speed is 30 sin(10°) = 5.209 meters per second.

The acceleration of gravity is 9.8 meters per second² downward.

The ball continues to rise for 9.8/5.209 = 1.881 seconds after the kick.
At that time, it reaches the peak of its arc, and if nobody else has contacted it yet,
it begins to fall, and takes the same length of time to return to the ground whence
it was kicked.

So the time between the kick and return to the ground is (2 x 1.881) = <u>3.763 seconds</u>.

Note: As is customary and necessary at the high school level,
we assume no air resistance.

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A rocket is fired at 100 m/s at an angle of 37, how many seconds is it in the air?

Sonbull [250]

Answer:

12.3 seconds

Explanation:

time in air = 2(v)/g

2(100sin(37))/9.8

=12.28 seconds

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3 years ago

Which term means that humans are combining two different organism's DNA to create a new organism. Hint: Oink, Oink Question 3 op

cestrela7 [59]

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3 years ago

A wire of Nichrome (a nickelâ€“ chromiumâ€“ iron alloy commonly used in heating elements) is 1.0 m long and 1.0 mmÂ² in cross-se

Lyrx [107]

Answer:

The conductivity of Nichrome is $2\times 10^6\ S/m$ .

Explanation:

Given:

Potential difference (V) = 2.0 V

Current flowing (I) = 4.0 A

Length of wire (L) = 1.0 m

Area of cross section of wire (A) = 1.0 mm² = 1 × 10⁻⁶ m² [1 mm² = 10⁻⁶ m²]

We know, from Ohm's law, that the ratio of voltage and current is always a constant and equal to the resistance of the resistor. Therefore, the resistance of the nichrome wire is given as:

$R=\frac{V}{A}=\frac{2.0}{4.0}=0.5\ \Omega$

Now, resistance of the nichrome wire in terms of its resistivity, length and area of cross section is given as:

$R=\rho\frac{L}{A}$

Where, $\rho\to resistivity\ of\ Nichrome$

Now, plug in all the values given and solve for $\rho$ . This gives,

$0.5\ \Omega=\rho\frac{1.0\ m}{1\times 10^{-6}\ m^2}\\\\\rho=\frac{0.5\times 1\times 10^{-6}}{1.0}=0.5\times 10^{-6}\ \Omega-m$

Now, conductivity of a material is the reciprocal of its resistivity. Therefore, the conductivity of Nichrome is given as:

$\sigma=\frac{1}{\rho}=\frac{1}{0.5\times 10^{-6}}=2\times 10^6\ S/m$

Conductivity is measured in Siemens per meter (S/m)

Therefore, the conductivity of Nichrome is $2\times 10^6\ S/m$ .

7 0

2 years ago

Human activities can have an impact on natural disasters.

kolezko [41]

I think you wanted to know whether the statement in question is true or false. Assuming this fact, i am answering the question and hope that it helps you. It is a true fact that human activities can have an impact on natural disasters. The increase in global temperature due to emission of greenhouse gases can cause the sea level to rise and create hurricanes.

6 0

3 years ago

Read 2 more answers

(i) Calculate the energy, in electron volts, of a photon whose frequency is (a) 620 THz}, (b) 3.10GHz , and(c) 46.0 MHz

DedPeter [7]

The energy in electron volts of the photons that has the following frequencies is as follows:

620 THz = 2.564eV
3.10GHz = 1.28 × 10-⁵eV
46.0 MHz = 1.902 × 10-⁷eV

<h3>How to calculate energy?</h3>

The energy of a photon can be calculated using the following formula:

E = hf

Where;

E = energy
h = Planck's constant (6.626 × 10-³⁴ J/s)
f = frequency

First, we convert the frequencies to hertz as follows;

620THz = 6.2 × 10¹⁴Hz
3.10GHz = 3.1 × 10⁹Hz
46.0MHz = 4.6 × 10⁷Hz

E = 6.626 × 10-³⁴ × 6.2 × 10¹⁴ = 2.564eV
E = 6.626 × 10-³⁴ × 3.1 × 10⁹ = 1.28 × 10-⁵eV
E = 6.626 × 10-³⁴ × 4.6 × 10⁷ = 1.902 × 10-⁷eV

Learn more about energy of a photon at: brainly.com/question/2393994

#SPJ1

6 0

1 year ago