How many sandwiches were made in the hour?

Two loudspeakers (A and B) are 3.20m apart and emitting a sound with a frequency of 400Hz. An observer is 2.10m directly in fron

TiliK225 [7]

Answer:

The observer hears a loud sound

Explanation:

In order to know if the observer hears a loud or a quiet sound, you need to know if there is a constructive or destructive interference between the sound waves of the loudspeakers.

You first calculate the distance between the observer and the loudspeakers.

The distances are given by:

d1: distance to loudspeaker A = 2.10m

d2: distance to loudspeaker B

$d_2=\sqrt{(3.20m)^2+(2.10m)^2}=3.827m$

Next, you calculate the wavelength of the sound waves by using the following formula:

$\lambda=\frac{v_s}{f}$

vs: speed of sound = 343 m/s

f: frequency of the waves = 400Hz

λ: wavelength

$\lambda=\frac{343m/s}{400Hz}=0.8575m$

Next, you calculate the path difference between the distance from the observer to the loudspeakers:

$\Delta d=3.827m-2.10m=1.727m$

You obtain a constructive interference (loud sound) if the quotient between the wavelength of the sound and the difference path is an integer:

$\frac{\Delta d}{\lambda}=\frac{1.727m}{0.857}\approx2$

Then, there will be a constructive interference, and the sound who the observer hears is loud.

5 0

3 years ago

Cart A, with a mass of 0.20 kg, travels on a horizontal air trackat 3.0m/s and hits cart B, which has a mass of 0.40 kg and is i

inysia [295]

Answer:

$\large \boxed{\text{C. 2.3 m/s}}$

Explanation:

Data:

$m_{\text{A} } = \text{0.20 kg};\,v_{\text{Ai}} = \text{3.0 m/s}\\m_{\text{B} } = \text{0.40 kg};\,v_{\text{Bi}} = \text{2.0 m/s}\\$

Calculation:

This is a perfectly inelastic collision. The two carts stick together after the collision and move with a common final velocity.

The conservation of momentum equation is

$\begin{array}{rcl}m_{\text{A}}v_{\text{Ai}} +m_{\text{B}} v_{\text{Bi}}&=&(m_{\text{A}} + m_{\text{B}})v_{\text{f}}\\0.20\times 3.0 + 0.40\times 2.0 & = & (0.20 + 0.40)v_{\text{f}}\\0.60 + 0.80 & = & 0.60v_{\text{f}}\\1.40 & = & 0.60v_{\text{f}}\\v_{\text{f}}&=& \dfrac{1.40}{0.60}\\\\& = & \textbf{2.3 m/s}\\\end{array}\\\text{The centre of mass has a velocity of $\large \boxed{\textbf{2.3 m/s}}$}$

3 0

3 years ago

Which sentence provides evidence that heat travels from Earth’s mantle up to its crust?

olasank [31]

B. Earth’s outer surface is cooler than its interior layers.

Explanation:

The option given above is showing us that the temperature in the interior of the earth is higher than the temperature in the outer layer.
There is travel of heat from the inner core of the earth to the earth's crust. Due to the loss of heat when it reaches the outer layer, there arises a temperature difference.
The heat loss is due to the absorption of heat during its transfer. Hence, option B is the answer.

7 0

3 years ago

7. Starting at rest, a car accelerates at 5.5m/s/s for 12s. What is its

Musya8 [376]

Answer:

66 m/s

Explanation:

v=u+at

= 0 + 5.5 * 12

= 66 m/s

6 0

2 years ago

State Newtons first law of motion.

Fofino [41]

Answer:

An object at rest will stay at rest and an object in motion will stay in motion unless it is acted upon by an unbalanced/external force.

8 0

3 years ago