Please I need HELP WITH THIS QUESTION!!!

Invasive species are _______ species that have a ______ impact on a given ecosystem.

S_A_V [24]

The answer is non-native, harmful.

7 0

3 years ago

A 4 kg bowling ball rolls at a speed of 5 m/s on the roof of a building that is 30 meters tall. What is its kinetic energy?

klasskru [66]

ans: B

Kinetic energy = $\frac{1}{2} mv^{2}$

= $\frac{1}{2} (4)(5^{2} )$

= 50J

ps. the height will only affect its potential energy, not kinetic.

3 0

3 years ago

A car is travelling with a velocity of 10 m/s and has a mass of 550 kg. The<br> car has<br> energy.

Elenna [48]

Answer: The car has a kinetic energy (because it's in motion) of: $27500J$

Explanation:

$Formula: E=\frac{1}{2}mv^2$

$E=\frac{1}{2}mv^2$

$E=\frac{1}{2}(550kg)(10m/s)^2$

$E=\frac{1}{2}(550kg)(100m^2/s^2)$

$E=\frac{1}{2}(55000J)\\E=27500J$

3 0

3 years ago

Uranium-235 decays to thorium-231 with a half-life of 700 million years. When a rock was formed, it contained 6400 million urani

Dahasolnce [82]

Answer:

proof in explanation

Explanation:

First, we will calculate the number of half-lives:

$n = \frac{t}{t_{1/2}}$

where,

n = no. of half-lives = ?

t = total time passed = 2100 million years

$t_{1/2}$ = half-life = 700 million years

Therefore,

$n = \frac{2100\ million\ years}{700\ million\ years}\\\\n = 3$

Now, we will calculate the number of uranium nuclei left ( $n_u$ ):

$n_u = \frac{1}{2^{n} }(total\ nuclei)\\\\n_u = \frac{1}{2^{3} }(6400\ million)\\\\n_u = \frac{1}{8}(6400\ million)\\\\n_u = 800\ million$

and the rest of the uranium nuclei will become thorium nuclei ( $u_{th}$ )

$n_{th} = total\ nuclei - n_u\\n_{th} = 6400\ million-800\ million\\n_{th} = 5600\ million$

dividing both:

$\frac{n_{th}}{n_u}=\frac{5600\ million}{800\ million} \\\\n_{th} = 7n_u$

<u>Hence, it is proven that after 2100 million years there are seven times more thorium nuclei than uranium nuclei in the rock.</u>

6 0

3 years ago

An RL circuit contains a resistor with R = 6800 Ω and an inductor with L = 2300 µH. If the impedance of this circuit is 160,000

Rainbow [258]

| Impedance | = √ [R² +(ωL)²]

R² = 6800² = 4.624 x 10⁷

(ωL)² = (2 · π · f · 2.3 · 10⁻³)²

= 2.0884 x 10⁻⁴ f²

| Z | = √[ (4.624 x 10⁷) + (2.0884 x 10⁻⁴ f²) ] = 1.6 x 10⁵

   (1.6 x 10⁵)² = (4.624 x 10⁷) + (2.0884 x 10⁻⁴ f²)

   (2.56 x 10¹⁰) - (4.624 x 10⁷) = 2.0884 x 10⁻⁴ f²

Frequency² = (2.56 x 10¹⁰ - 4.624 x 10⁷) / 2.0884 x 10⁻⁴

      = 2.555 x 10¹⁰ / 2.0884 x 10⁻⁴

=    1.224 x 10¹⁴

      =      122,400 GHz    <== my calculation

    11.1 MHz <== online impedance calculator

Obviously, I must have picked up some rounding errors
in the course of my calculation.

7 0

3 years ago