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3 years ago

Each bat can produce different frequencies of ultrasound. Explain why this is useful if there are many bats hunting together.

1 answer:

6 0

Answer: Although low frequency sound travels further than high-frequency sound, calls at higher frequencies give the bats more detailed information--such as size, range, position, speed and direction of a prey's flight. Thus, these sounds are used more often.

Explanation:

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Factors affecting speed of sound in air

zhannawk [14.2K]

Answer:

The Density of Medium: Sound requires a medium to travel. The density of the medium is among the factors which affect the speed of sound. ...

The Temperature of The Medium: Higher the temperature, the higher is the speed of sound in the medium.

Explanation:

hope it helps

4 0

3 years ago

Read 2 more answers

For what value of the ratio r/a of plate radius to separation between the plates does the electric field at the point x=a/2 on t

SIZIF [17.4K]

solution:

E\delta =\frac{R}{\epsilon0}(1-\frac{A}{\sqrt{4R^{2}}-ac}

=\frac{R}{\epsilon0}(1-\frac{1}{\sqrt{4r^{2}/^{_a{2}}+1}})

=\frac{R}{\epsilon0}(1-\frac{1}{\sqrt{4x^2+1}})

x=\frac{r}{a}

infinite case,

Ei=\frac{r}{\epsilon0}

\therefore e\delta =ei(1-\frac{1}{\sqrt{4x^{2}+1}})

we have to find x when,

ei-e\delta =1% ,y=ei=1/100 ei

or,ei-ei+\frac{ei}{\sqrt{4x^2+1}} = 1/100ei

\frac{1}{\sqrt{4x^2+1}}=\frac{1}{100}

4x^2+1 =10^4

x=\frac{\sqrt{\frac{10^4-1}{4}}}=49.99\approx 50

\therefore \frac{r}{a}\approx 50

6 0

3 years ago

Canadian Olivia Oliver broke the Guinness World Record for the fastest spin on ice skates on January 2015 with an angular veloci

Shalnov [3]

Answer:

Explanation:

initial angular velocity ω' = 130 rpm

final angular velocity ω = 342 rpm

recall that angular momentum = ωI

where I is the moment of inertia.

for the initial spinning condition, we take moment of inertial = I'

for final spinning condition, we take moment of inertia = I

initial angular momentum = ω'I' = 130 I'

final angular momentum = ωI = 342 I

according to conservation of angular momentum, initial angular momentum must be equal to the final angular momentum, therefore

342 I = 130 I'

ratio of initial moment of inertia to final moment of inertia = I'/I

==> I'/I = 342/130 ≅ <em>2.63 : 1</em>

b) to achieve a final angular velocity of of 375 rpm, her initial velocity will have to be

2.63 = 375/ω'

ω' = 375/2.63 = <em>143.13 rpm</em>

6 0

3 years ago

A ball falls from the top of a building. As it falls, its speed increases. Which type of energy is the ball gaining as it falls?

Elina [12.6K]

<h2>Hello!</h2>

The answer is: B. Kinetic energy

Since the ball is falling, speed increases because the gravity acceleration is acting. When speed increases, the kinetic energy increases too, so the ball is gaining kinetic energy.

The gravity acceleration is equal to $9.81\frac{m}{s^{2}}$ , it means that when falling, the ball will increase it's speed 9.81m every second.

We can calculate the kinetic energy by using the following formula:

$KE=\frac{1}{2}*m*v^{2}$

Where:

$m=mass\\v=velocity$

Have a nice day!

<h2 />

5 0

4 years ago

The ball of a ballpoint pen is 0.5 mm in diameter and has an ASTM grain size of 12. How many grainsare there in the ball

Alina [70]

Answer:

the number of grains in the ball is 274,848

Explanation:

Given that;

diameter = 0.5 mm

so radius r = 0.25 mm

first we determine the volume of the ball using the following equation;

V = 4/3×πr³

we substitute

V = 4/3×π(0.25)³

V = 0.06544 mm³

Now form table 1.1 "Grain sizes" a metal with grain size number of 12 has about 4,200,000 grains/mm³

so;

Number of grains N = 0.06544 × 4,200,000

N = 274,848 grains

Therefore, the number of grains in the ball is 274,848

5 0

3 years ago