Dab
10. <span>A block with mass m = 6.2 kg is attached to two springs with spring constants kleft = 31.0 N/m and kright = 49.0 N/m. The block is pulled a distance x = 0.2 m to the left of its equilibrium position and released from rest
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Answer:
35 J
Explanation:
The man is holding the box: this means that he is applying a force vertically upward, to balance the weight of the box (which pushes downward).
Therefore, we can ignore the horizontal displacement of the man, because the force applied (vertically upward) is perpendicular to that displacement (horizontal), so the work done for that is zero.
So, only the vertical motion contributes to the work. The work done by the man is equal to the gain in gravitational potential energy of the box, so:
where
is the weight of the box
is the vertical displacement
Substituting, we find
<span>The key equation is going to come from Mr Planck: E=h \nu
Where h is Plancks constant; and ν is the frequency. This equation gives you the energy per photon at a given frequency. Alas, you're given wavelength, but that's easy enough to convert to frequency given the following equation:
c= lambda / nu
where c is the speed of light; λ (lambda) is the wavelength; and ν is again frequency. As soon as you know the energy of a photon with a wavelength of 550nm, you should know how many photons you would require to accumulate 10^-18J. Be careful with your units.</span>
Protons, neutrons and electrons. Both protons and neutrons have a mass of 1 amu and are found in the nucleus. However, protons have a charge of +1, and neutrons are uncharged. Electrons have a mass of approximately 0 amu, orbit the the nucleus, and have a charge of -1.
