What is the wavelength of an AM radio wave in a vacuum if its frequency is 810 kHz?

Water at 20oC flows through a long elliptical duct 30 cm wide and 22 cm high. What average velocity, in m/s, would cause the wei

mars1129 [50]

Explanation:

The given data is as follows.

Fluid is water so, density $\rho = 1000 kg/m^{3}$

Weight flow rate = 500 lbf/s = 2224.11 N/sec

Cross-sectional area (A) = $\pi \times \frac{30}{2} \times \frac{22}{2}$

= 0.05184 $m^{2}$

Hence, weight flow rate will be given as follows.

w = $\rho \times g \times A \times V$

2224.11 N/sec = $\rho \times g \times A \times V$

V = $\frac{2224.11}{1000 \times 9.81 \times 0.05184}$ m/s

= 4.373 m/s

Thus, we can conclude that average velocity in the given case is 4.373 m/s.

8 0

3 years ago

Read 2 more answers

I need a short answer ?

mars1129 [50]

Answer:

Explanation:

7a) t = d/v = 100/45cos14.5 = 2.29533...= 2.30 s

7b) h = ½(9.81)(2.29533/2)² = 6.46056... = 6.45 m

or

h = (45sin14.5)² / (2(9.81)) = 6.47 m

which rounds to the same 6.5 m when limiting to the two significant digits of the initial velocity.

7 0

3 years ago

Lifting a box off the floor is an example of what type of force?

s2008m [1.1K]

Gravitational I think would be the answer, Hope this helps!

8 0

3 years ago

Read 2 more answers

If the Sun suddenly went dark, we would not know it until its light stopped arriving on Earth. How long would that be, in second

Gre4nikov [31]

Answer: 500 s

Explanation:

Speed $v$ is defined as a relation between the distance $d$ and time $t$ :

$v=\frac{d}{t}$

Where:

$v=3(10)^{8}m/s$ is the speed of light in vacuum

$d=1.5(10)^{11}m$ is the distance between the Earth and Sun

$t$ is the time it takes to the light to travel the distance $d$

Isolating $t$ :

$t=\frac{d}{v}$

$t=\frac{1.5(10)^{11}m}{3(10)^{8}m/s}$

Finally:

$t=500 s$

5 0

3 years ago

The maximum energy a bone can absorb without breaking is surprisingly small. For a healthy human of mass 60 kg60 kg, experimenta

netineya [11]

Answer:

the maximum height a man can jump from and land rigidly upright on both feet without breaking his legs is 0.34 m

Explanation:

Mass of a healthy man = 60 kg

energy the bone can take without breaking = 200 J

If a healthy man jumps from a height 'h', he falls with an energy equal to the potential energy due to his initial height above the ground.

initial potential energy of the healthy man = mgh

where m = mass of the man

g = acceleration due to gravity = 9.81 m/s^2

h = the height above ground

==> PE = 60 x 9.81 x h = 588.6h

If we assume that all energy is absorbed in the leg bones in a rigid landing, then we can safely say that this calculated PE for a healthy man is equal to the energy his bone can absorb in the jump without breaking.

equating, we have

200 = 588.6h

the maximum height a man can jump from without breaking his legs = 200/588.6 = 0.34 m

When people jump from a height, the sudden deceleration to zero can impact a big force on the leg bones, shattering them. If the time spent in decelerating to zero is increased, the overall force on the leg bones is reduced greatly.

Bending the knees gradually on landing from a jump from a height, and then rolling increases the time spent decelerating, and reduces the impact force on the legs due to the landing. If you observe carefully you will see that this is what professional stunts men and acrobats do when they jump from a height.

5 0

3 years ago