Hi. The language here looks as though it's Spanish/Portugese ??? It would help to answer the q if the q were posted in english. I speak a little spanish and french, but it's mostly guesswork.
The horizontal force needed to start the calculator moving from rest is 1.5 N
What is Kinetic friction?
It is defined as a force that acts between moving surfaces.
The magnitude of the force will depend on the coefficient of kinetic friction between the two materials.
Here,
weight of calculator, N = 3 N
The coefficients of static frictions, µ (static) = 0.50
The coefficients of kinetic frictions, µ (kinetic) = 0.40
Now,
The horizontal force required = The static friction force
F = µ (static) * weight of calculator
F = 0.50 * 3.0
F = 1.5 N
Hence,
The horizontal force needed to start the calculator moving from rest is 1.5 N
Learn more about horizontal force here:
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Answer:
C. a clamp light with a 150-W lightbulb placed 25 cm from the radiometer
Explanation:
because the temperature has to be set, meaning it can't change, and it should be a different distance away than the first one.
Hope this helps! Stay safe!
Answer:
The pressure is 6570 lbf/ft²
The temperature is 766 ⁰R
The velocity is 2746.7 ft/s
deflection angle behind the wave is 17.56⁰
Explanation:
Speed of air at initial condition:

γ is the ratio of specific heat, R is the universal gas constant, and T is the initial temperature.
initial mach number

then, 
based on the values obtained, read off the following from table;
P₂/P₁ = 3.285
T₂/T₁ = 1.473
Mₙ₂ = 0.6355
Thus;
P₂ = 3.285P₁ = 3.285(2000) = 6570 lbf/ft²
T₂ = 1.473T₁ = 1.473(520⁰R) = 766 ⁰R
Again; to determine the velocity and deflection angle, first we calculate the mach number.





Answer:
6538.8 Angstrom
Explanation:
work function, w = 1.9 eV = 1.9 x 1.6 x 10^-19 J = 3.04 x 10^-19 J
Let the longest wavelength is λ.
W = h c / λ
λ = h c / W
λ = (6.626 x 10^-34 x 3 x 10^8) / (3.04 x 10^-19)
λ = 6.5388 x 10^-7 m = 6538.8 Angstrom
Thus, the longest wavelength is 6538.8 Angstrom.