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3 years ago

If the number of wavelengths that pass a point in a given time increases, what has increased?

Physics

2 answers:

Shtirlitz [24]3 years ago

8 0

A /////////////////////////////

alex41 [277]3 years ago

4 0

A:))))))))))) ;))))))

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Consider a father pushing a child on a playground merry-go-round. The system has a moment of inertia of 84.4 kg.m^2. The father

Sophie [7]

Answer:

Explanation:

Given that:

the initial angular velocity $\omega_o = 0$

angular acceleration $\alpha$ = 4.44 rad/s²

Using the formula:

$\omega = \omega_o+ \alpha t$

Making t the subject of the formula:

$t= \dfrac{\omega- \omega_o}{ \alpha }$

where;

$\omega = 1.53 \ rad/s^2$

∴

$t= \dfrac{1.53-0}{4.44 }$

t = 0.345 s

Using the formula:

$\omega ^2 = \omega _o^2 + 2 \alpha \theta$

here;

$\theta$ = angular displacement

∴

$\theta = \dfrac{\omega^2 - \omega_o^2}{2 \alpha }$

$\theta = \dfrac{(1.53)^2 -0^2}{2 (4.44) }$

$\theta =0.264 \ rad$

Recall that:

2π rad = 1 revolution

Then;

0.264 rad = (x) revolution

$x = \dfrac{0.264 \times 1}{2 \pi}$

x = 0.042 revolutions

Here; force = 270 N

radius = 1.20 m

The torque = F * r

$\tau = 270 \times 1.20 \\ \\ \tau = 324 \ Nm$

However;

From the moment of inertia;

$Torque( \tau) = I \alpha \\ \\ Since( I \alpha) = 324 \ Nm. \\ \\ Then; \\ \\ \alpha= \dfrac{324}{I}$

given that;

I = 84.4 kg.m²

$\alpha= \dfrac{324}{84.4} \\ \\ \alpha=3.84 \ rad/s^2$

For re-tardation; $\alpha=-3.84 \ rad/s^2$

Using the equation

$t= \dfrac{\omega- \omega_o}{ \alpha }$

$t= \dfrac{0-1.53}{ -3.84 }$

$t= \dfrac{1.53}{ 3.84 }$

t = 0.398s

The required time it takes= 0.398s

5 0

3 years ago

A 771.0-kg copper bar is melted in a smelter. The initial temperature of the copper is 300.0 K. How much heat must the smelter p

Dovator [93]

Answer:

4.73 × 10^5

Explanation:

6 0

3 years ago

An electric fan is turned off, and its angular velocity decreases uniformly from 500 rev/min to 200 rev/min in 4.00 s.

Veseljchak [2.6K]

Answer:

a) -1.25 rev/s² and 23.3 rev

b) 2.67s

Explanation:

a) ω $Ф_o_z$ = (500 rev/min)(1min/ 60s) => 8.333 rev/s

ω $Ф_Z$ = (200 rev/min)(1min/ 60s) => 3.333rev/s

time 't'= 4 s

angular acceleration 'α $Ф_Z$ '=?

constant angular acceleration equation is given by,

ω $Ф_Z$ = ω $Ф_o_z$ + α $Ф_Z$ t

α $Ф_Z$ = (ω $Ф_Z$ - ω $Ф_o_z$ )/t => (3.333-8.333)/4

α $Ф_Z$ = -1.25 rev/s²

θ-θ $Ф_o$ = ω $Ф_o_z$ t + 1/2α $Ф_Z$ t²

=(8.333)(4) + 1/2 (-1.25)(4)²

=23.3 rev

b) ω $Ф_Z$ =0 (comes to rest)

ω $Ф_o_z$ = 3.333 rev/s

α $Ф_Z$ = -1.25 rev/s²

ω $Ф_Z$ = ω $Ф_o_z$ + α $Ф_Z$ t

t= (ω $Ф_Z$ - ω $Ф_o_z$ )/α $Ф_Z$ => (0- 3.333)/-1.25

t= 2.67s

3 0

3 years ago

Compare blue and red light from the visible spectrum. which has: the longer wavelength? the greater frequency? the greater energ

Hitman42 [59]

1) By looking at the table of the visible spectrum, we see that blue light has a wavelength in the range [450-490 nm], while red light has wavelength in the range [620-750 nm]. Therefore, red light has longer wavelength than blue light.

2) The frequency f of an electromagnetic wave is related to its wavelength $\lambda$ by the formula
$f= \frac{c}{\lambda}$
where c is the speed of light. We see that the frequency is inversely proportional to the wavelength, so the shorter the wavelength, the greater the frequency. In this case, blue light has shorter wavelength than red light, so blue light has greater frequency than red light.

3) The energy of the photons of an electromagnetic wave is given by
$E=hf$
where h is the Planck constant and f is the frequency. We see that the energy is directly proportional to the frequency, so the greater the frequency, the greater the energy. In this problem, blue light has greater frequency than red light, so blue light has also greater energy than red light.

6 0

3 years ago

In a local bar, a customer slides an empty beer mug down the counter for a refill. The height of the counter is 1.42 m. The mug

telo118 [61]

Answer:

a) $V_{x}=3.72m/s$ , b) ∠=-54.83°

Explanation:

In order to solve this problem, we must start with a drawing of the situation, this will help us visualize the problem better. (See picture attached).

Now, the idea is that the beer mug has a horizontal speed and no vertical speed at initial conditions. So knowing this, we can start finding the initial velocity of the mug.

In order to do so, we need to find the time it takes for the mug to reach the ground. We can find it by using the following equation:

$y=y_{0}+V_{y0}t+\frac{1}{2}a_{y}t^{2}$