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3 years ago

What is the number of wavelengths that pass a given point each second called?

1 answer:

4 0

Since waves are moving, we define frequency as the number of waves that pass a given point in a specified unit of time. The unit commonly used is Hertz which is the number of wave cycles that pass a point in one second.

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Over the past 150 years, what has happened to the amount of forest cover in Minnesota?

Airida [17]

I think D. None of the above

I think that it

4 0

3 years ago

A cooling fan is turned off when it is running at 850 rev/min. It turns 1500 revolutions before it comes to a stop. (a) What was

8_murik_8 [283]

Answer

given,

cooling fan revolution = 850 rev/min

fan turns before revolution = 1500 revolutions

$\omega = 850 \dfrac{2\pi}{60}$

$\omega = 89\ rad/s$

θ = 1500 revolution

θ = 1500 x 2 x π

θ = 9424.78 rad

a) using equation of rotation

ω² = ω₀² + 2 α θ

ω = 0 because body comes to rest

0 = 89² + 2 x α x 9424.78

α = -0.42 rad/s²

b) time take for the fan to stop

ω = ω₀ + α t

0 = 89 - 0.42 t

$t = \dfrac{89}{0.42}$

t = 211.9 s

5 0

3 years ago

A cue ball has a mass of 0.5 kg. During a game of pool, the cue ball is struck and now has a velocity of 3 . When it strikes a s

photoshop1234 [79]

Answer: 3 m/s

Explanation:

We can solve the problem by using the law of conservation of momentum: during the collision between the two balls, the total momentum of the system before the collision and after the collision must be conserved:

$p_i = p_f$

The total momentum before the collision is given only by the cue ball, since the solid ball is initially at rest, therefore

$p_i = m_c u_c = (0.5 kg)(3 m/s)=1.5 kg m/s$

So, the final total momentum will also be

$p_f = 1.5 kg m/s$

And the total momentum after the collision is given only by the solid ball, since the cue ball is now at rest, therefore:

$p_f = m_s v_s$

from which we find the velocity of the solid ball

$v_s = \frac{p_f}{m_s}=\frac{1.5 kg m/s}{0.5 kg}=3 m/s$

8 0

3 years ago

Read 2 more answers

An airliner arrives at the terminal, and its engines are shut off. The rotor of one of the engines has an initial clockwise angu

Ilia_Sergeevich [38]

(a) 1200 rad/s

The angular acceleration of the rotor is given by:

$\alpha = \frac{\omega_f - \omega_i}{t}$

where we have

$\alpha = -80.0 rad/s^2$ is the angular acceleration (negative since the rotor is slowing down)

$\omega_f$ is the final angular speed

$\omega_i = 2000 rad/s$ is the initial angular speed

t = 10.0 s is the time interval

Solving for $\omega_f$ , we find the final angular speed after 10.0 s:

$\omega_f = \omega_i + \alpha t = 2000 rad/s + (-80.0 rad/s^2)(10.0 s)=1200 rad/s$

(b) 25 s

We can calculate the time needed for the rotor to come to rest, by using again the same formula:

$\alpha = \frac{\omega_f - \omega_i}{t}$

If we re-arrange it for t, we get:

$t = \frac{\omega_f - \omega_i}{\alpha}$

where here we have

$\omega_i = 2000 rad/s$ is the initial angular speed

$\omega_f=0$ is the final angular speed

$\alpha = -80.0 rad/s^2$ is the angular acceleration

Solving the equation,

$t=\frac{0-2000 rad/s}{-80.0 rad/s^2}=25 s$

6 0

3 years ago

A hawk leaves its nest in Fort Worth and travels 3,000 meters east. After snacking on a tasty rodent the hawk flies another 1,50

Paha777 [63]

I think the logical question here is to either find the distance or the displacement. They differ in such a way that distance is a scalar quantity that does not focus on the direction. Displacement is a vector quantity that covers the distance from the starting point to end point. Because it travels only in one direction (to the east), in this condition, distance is equal to displacement.

Distance = Displacement = 3,000 m + 1,500 m = 4,500 m

6 0

3 years ago