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3 years ago

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A group of students left school at 8:00 am on a field trip to a science museum 90 miles away. Which best describes the average s

peed of the bus if they arrived at the museum at 10:00 am?

1 answer:

Aliun [14]3 years ago

7 0

Answer:

45

Explanation:

because the equation for speed is distance divided by time! hope that helps gave a nice day!

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Water (density = 1x10^3 kg/m^3) flows at 15.5 m/s through a pipe with radius 0.040 m. The pipe goes up to the second floor of th

RUDIKE [14]

Answer:

The speed of the water flow in the pipe on the second floor is approximately 13.1 meters per second.

Explanation:

By assuming that fluid is incompressible and there are no heat and work interaction through the line of current corresponding to the pipe, we can calculate the speed of the water floor in the pipe on the second floor by Bernoulli's Principle, whose model is:

$P_{1} + \frac{\rho\cdot v_{1}^{2}}{2}+\rho\cdot g\cdot z_{1} = P_{2} + \frac{\rho\cdot v_{2}^{2}}{2}+\rho\cdot g\cdot z_{2}$ (1)

Where:

$P_{1}$ , $P_{2}$ - Pressures of the water on the first and second floors, measured in pascals.

$\rho$ - Density of water, measured in kilograms per cubic meter.

$v_{1}$ , $v_{2}$ - Speed of the water on the first and second floors, measured in meters per second.

$z_{1}$ , $z_{2}$ - Heights of the water on the first and second floors, measured in meters.

Now we clear the final speed of the water flow:

$\frac{\rho\cdot v_{2}^{2}}{2} = P_{1}-P_{2}+\rho \cdot \left[\frac{v_{1}^{2}}{2}+g\cdot (z_{1}-z_{2}) \right]$

$\rho\cdot v_{2}^{2} = 2\cdot (P_{1}-P_{2})+\rho\cdot [v_{1}^{2}+2\cdot g\cdot (z_{1}-z_{2})]$

$v_{2}^{2}= \frac{2\cdot (P_{1}-P_{2})}{\rho}+v_{1}^{2}+2\cdot g\cdot (z_{1}-z_{2})$

$v_{2} = \sqrt{\frac{2\cdot (P_{1}-P_{2})}{\rho}+v_{1}^{2}+2\cdot g\cdot (z_{1}-z_{2}) }$ (2)

If we know that $P_{1}-P_{2} = 0\,Pa$ , $\rho=1000\,\frac{kg}{m^{3}}$ , $v_{1} = 15.5\,\frac{m}{s}$ , $g = 9.807\,\frac{m}{s^{2}}$ and $z_{1}-z_{2} = -3.5\,m$ , then the speed of the water flow in the pipe on the second floor is:

$v_{2}=\sqrt{\left(15.5\,\frac{m}{s} \right)^{2}+2\cdot \left(9.807\,\frac{m}{s^{2}} \right)\cdot (-3.5\,m)}$

$v_{2} \approx 13.100\,\frac{m}{s}$

The speed of the water flow in the pipe on the second floor is approximately 13.1 meters per second.

4 0

3 years ago

Define the fundamental difference between kinematics and dynamics. .

Tcecarenko [31]

In kynematics you describe the motion of particles using vectors and their change in time. You define a position vector r for a particle, and then define velocity v and acceleration a as

$v=\frac{dr}{dt} \\$

$a=\frac{dv}{dt}$

In dynamics Newton's laws predict the acceleration for a given force. Knowing the acceleration, and the kynematical relations defines above, you can solve for the position as a function of time: r(t)

5 0

3 years ago

What type of energy transformation is taking place when natural gas is used to heat water

bazaltina [42]

Thermal energy transformation is taking place.

3 0

3 years ago

radio waves travel at the speed of light, 3 x 10^8 m/s. the wavelength of a radio wave record is 200,000,000 hz is?

ludmilkaskok [199]

Answer:

1.5m

Explanation:

Speed of waves is given as the product of the wavelength and frequency. Sometimes when frequency is not given but the period is given, we get the frequency as the reciprocal of the period. The speed of waves is given in m/s, wavelength in m while frequency in Hz.

Speed, s= fw and making w the subject of formula,

$w=\frac {s}{f}$

Substituting 300, 000, 000 m/s for s and 200, 000, 000 for f then we obtain that

$w=\frac {300000000}{200000000}=1.5 m$

6 0

3 years ago

Two lasers are shining on a double slit, with slit separation d. Laser 1 has a wavelength of d/20, whereas laser 2 has a wavelen

Marta_Voda [28]

Answer:

a) that laser 1 has the first interference closer to the central maximum

c) Δy = 0.64 m

Explanation:

The interference phenomenon is described by the expression

d sin θ = m λ

Where d is the separation of the slits, λ the wavelength and m an integer that indicates the order of interference

For the separation of the lines we use trigonometry

tan θ = sin θ / cos θ = y / x

In interference experiments the angle is very small

tan θ = sin θ = y / x

d y / x = m λ

a) and b) We apply the equation to the first laser

λ = d / 20

d y / x = m d / 20

y = m x / 20

y = 1 4.80 / 20

y = 0.24 m

The second laser

λ = d / 15

d y / x = m d / 15

y = m x / 15

y = 0.32 m

We can see that laser 1 has the first interference closer to the central maximum

c) laser 1

They ask us for the second maximum m = 2

y₂ = 2 4.8 / 20

y₂ = 0.48 m

For laser 2 they ask us for the third minimum m = 3

In this case to have a minimum we must add half wavelength

y₃ = (m + ½) x / 15

m = 3

y₃ = (3 + ½) 4.8 / 15

y₃ = 1.12 m

Δy = 1.12 - 0.48

Δy = 0.64 m

4 0

3 years ago