Frequency = (speed) / (wavelength) = 20 / 0.5 = 40 per second = 40 Hz.
One hertz means that an event repeats one per second so the unit for measuring frequency is the hertz and the answer is A.hertz :)))
i hope this be helpful
Answer:
Physical Properties of Sodium
Atomic number 11
Melting point 97.82°C (208.1°F)
Boiling point 881.4°C (1618°F)
Volume increase on melting 2.70%
Latent heat of fusion 27.0 cal/g
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Home Periodic table Elements Sodium
Sodium - Na
Chemical properties of sodium - Health effects of sodium - Environmental effects of sodium
Atomic number
11
Atomic mass
22.98977 g.mol -1
Electronegativity according to Pauling
0.9
Density
0.97 g.cm -3 at 20 °C
Melting point
97.5 °C
Boiling point
883 °C
Vanderwaals radius
0.196 nm
Ionic radius
0.095 (+1) nm
Isotopes
3
Electronic shell
[Ne] 3s1
Energy of first ionisation
495.7 kJ.mol -1
1) -76.27
2)-119.47
3)-256.27
4)-87.07
Here’s the formula for the last one so you know how to do it. Hope this helps!!!
Answer:
x = 3.6 [m]
Explanation:
This problem can be easily solved using a static analysis of forces acting on the ladder, taking into account the respective distances. For easy understanding, a free body diagram should be made.
We perform a sum of force on the X-axis equal to zero, to find that the force exerted by the wall is equal to the friction force on the floor.
Then we perform a summation of forces on the Y axis, to determine that the normal force exerted by the floor is equal to the weight of the ladder.
We know that the friction force is equal to the product of normal force by the coefficient of friction.
In this way, by relating the friction force to the equations deduced above we can find the force exerted by the wall.
Then we make a summation of moments around the base point of the ladder, the equation realized can be seen in the attached image.
In the last analysis we can find the relationship between the horizontal and vertical distance of the ladder, with respect to the wall and the floor.
Then with the complementary analysis of the Pythagorean theorem we can find another additional equation.
The result of the greater distance is 3.6 [m]