If an object is moving with a constant velocity, then by definition it has zero acceleration. So there is no net force acting on the object. The total work done on the object is thus 0 (that's not to say that there isn't work done by individual forces on the object, but the sum is 0 ).
Answer:
In particle physics, a lepton is an elementary particle of half-integer spin (spin 1⁄2) that does not undergo strong interactions.[1] Two main classes of leptons exist: charged leptons (also known as the electron-like leptons or muons), and neutral leptons (better known as neutrinos). Charged leptons can combine with other particles to form various composite particles such as atoms and positronium, while neutrinos rarely interact with anything, and are consequently rarely observed. The best known of all leptons is the electron.
Answer:
(a) 58 cm
(b) 591.4 Hz
(c) 246.5 cm
Explanation:
(a)
For closed organ pipe, the wavelength is given by
where 
is wavelength, L is the length of the pipe and n is the resonance
Substituting 217.5 m for L and 8 for n then the wavelength of the sound will be
(b)
We know that the speed of sound, v is a product of frequency and wavelength.
Making frequency the subject of the formula then
and since the velocity is given as 343 m/s and wavelength is already found in part a above but now we change units from cm to m then
(c)
We know that
The next resonance will be the 9th and we know the wavelength hence making L the subject then
Answer: 
Explanation:
The heat (thermal energy) absorbed by the iron skillet can be found using the following equation:
(1)
Where:
is the heat (absorbed)
is the mass of the element (iron in this case)
is the specific heat capacity of the material. In the case of iron is 
is the variation in temperature
Knowing this, lets rewrite (1) with these values:
(2)
Finally:
Answer:
1. the robber carrying the metal safe will hurt more because the metal safe is heavier, so the heavier will be the force on the opposite direction from the one he was running when he hit the wall
2. ???
Explanation:
1. 3rd newton law: "If two bodies exert forces on each other, these forces are equal in magnitude and opposite in direction"
2. I don't know
