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2 years ago

True or false: In order to create a sound wave, work must be done.

1 answer:

4 0

True - Because a sound wave carries energy; to propagate energy, energy must be applied for the sound wave to carry energy.

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What does the slope of a secant line represent

blsea [12.9K]

Answer:

Secant line is a straight line which joins the two points of functions and it also represents the slope between two points.

Explanation:

Secant line is also known as average rate of change of functions between two points and also called slope.

In mathematical form,

Secant line = average rate of change = slope

Slope m = y/x

3 0

3 years ago

"A 75 kg swimmer dives horizontally off a 500 kg raft. If the diver's speed immediately after leaving the raft is 4 m/s, what is

svet-max [94.6K]

Answer:

0.6 m/s

Explanation:

Let the raft speed be v.

Given:

Mass of the swimmer (m) = 75 kg

Mass of the raft (M) = 500 kg

Speed of swimmer after leaving the raft (u) = 4 m/s

Now, the given situation can be considered a problem of conservation of total momentum before and after collision.

Momentum is the product of mass and velocity.

Here, the swimmer and raft are the bodies in collision.

So, before the collision, both the bodies were at rest. So, initial momentum is 0. Now, from conservation of momentum, the final momentum of the system must be 0 after the collision. Therefore,

Final Momentum = 0

$mu+Mv=0\\\\Mv=-mu\\\\v=-\dfrac{mu}{M}$

Plug in the given values and solve for 'v'. This gives,

$v=-\frac{75\times 4}{500}\\\\v=-\frac{300}{500}=-0.6\ m/s$

The final velocity of the raft is -0.6 m/s. Now, speed is the magnitude of velocity.

Therefore, the corresponding raft speed is 0.6 m/s.

7 0

4 years ago

A square wave has amplitude 0 V for the low voltage and 4 V for the high voltage. Calculate the average voltage by integrating o

Margarita [4]

Answer:

V_{average} = $\frac{1}{2} V_o$ , V_{average} = 2 V

Explanation:

he average or effective voltage of a wave is the value of the wave in a period

V_average = ∫ V dt

in this case the given volage is a square wave that can be described by the function

V (t) = $\left \{ {{V=V_o \ \ \ t< \tau /2} \atop {V=0 \ \ \ \ t> \tau /2 } } \right.$

to substitute in the equation let us separate the into two pairs

V_average = $\int\limits^{1/2}_0 {V_o} \, dt + \int\limits^1_{1/2} {0} \, dt$

V_average = $V_o \ \int\limits^{1/2}_0 {} \, dt$

V_{average} = $\frac{1}{2} V_o$

we evaluate V₀ = 4 V

V_{average} = 4 / 2)

V_{average} = 2 V

6 0

3 years ago

A 70.0-kg person rides in an elevator while standing on a scale. the scale reads 896 n. what is the magnitude and direction acce

Ksju [112]

If the elevator was stationary, the scale would read exactly the weight of the person:
$W=mg=(70 km)(9.8 m/s^2)=686 N$
However, the elevator is moving with an acceleration a, so the scale reads a new value of the weight, which we call W'. Newton's second law becomes
$W' = ma'$
where a' is actually the total acceleration of the person, so it's the sum of the acceleraion of the elevator and of the gravitational acceleration: $a'=a+g$
Taking the direction of g (downward) as the positive direction, we can find the value of a:
$W' = m(a+g)$
$a= \frac{W'}{m}-g= \frac{896 N}{70 kg}-9.8 m/s^2=3 m/s^2$
So, the acceleration of the elevator is $3 m/s^2$ , with same sign of g, so it's directed downward as well.

4 0

4 years ago

A 12.0 g sample of gas occupies 19.2 L at STP. what is the of moles and molecular weight of this gas?

lubasha [3.4K]

At STP, 1 mole of an ideal gas occupies a volume of about 22.4 L. So if n is the number of moles of this gas, then

n / (19.2 L) = (1 mole) / (22.4 L) ==> n = (19.2 L•mole) / (22.4 L) ≈ 0.857 mol

If the sample has a mass of 12.0 g, then its molecular weight is

(12.0 g) / n ≈ 14.0 g/mol

4 0

3 years ago