Positive electric charge Q is distributed uniformly along a thin rod of length 2a. The rod lies along the x-axis between x = -a
1 answer:
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Answer:
D. Top is emission; bottom absorption.
Explanation:
Emission and spectrum of elements are due to the element absorbing or emitting wavelength of e-m energy. Elementary particles of elements can absorb energy from a ground state to enter an excited state, creating an absorption spectrum, or they can lose energy and fall back to a lower energy state, creating an emission spectrum. A simple rule to differentiate between an emission and an absorption spectrum is that: "all absorbed wavelength is emitted, but not all emitted wavelength is absorbed."
From the image, the lines indicates wavelengths. We can see that all of the wavelengths of the bottom absorption spectrum coincides with some of the wavelength of the upper emission wavelengths.
Answer:
B) 225 m/s^2
Explanation:
The rock hits the ground at 15m/s and travels 50cm=0.5m through the ground until it stops.
The acceleration is supposed to be uniform, so the formula we have to use is , which for acceleration is:
Taking the <em>downwards direction as positive</em> (the direction of traveling, so the initial velocity and displacement will be positive), substituting our values for that movement we have:
Where the <em>negative sign indicates that it is pointing upwards.</em>
Answer:
(a) 8.4375 s
(b) 1409.06 ft
(c) 40.55 seconds
Explanation:
v’(t)=a(t)=60t therefore
For first three seconds
Since motion is vertical and we take upward direction as positive, acceleration is negative hence
a(t)=-32 and but since at t=0 then v=270 hence c=270
-32.2t+270=0 hence
t=270/32=8.4375 s
(b)
and since s(0)=270 then
(c)
v(15)=-32(14)+270=-178 ft/s
Average speed in the next 5 seconds becomes
The altitude is 914-490=424 ft
Time when rocket hits ground
Total time=3+14+23.6=40.55 seconds