a substance's density is the same at a certain pressure and temperature, and the density of one substance is usually different than another substance.
Answer:
E = 31.329 N/C.
Explanation:
The differential electric field at the center of curvature of the arc is
<em>(we have a cosine because vertical components cancel, leaving only horizontal cosine components of E. )</em>
where is the radius of curvature.
Now
,
where is the charge per unit length, and it has the value
Thus, the electric field at the center of the curvature of the arc is:
Now, we find and . To do this we ask ourselves what fraction is the arc length 3.0 of the circumference of the circle:
and this is
radians.
Therefore,
evaluating the integral, and putting in the numerical values we get:
Answer:
Explanation:
We need the power equation here:
P = W/t where W is work and is defined as
W = F*displacement.
Force is a measure in Newtons, which is also weight. We have the mass of the piano, but we need to find the weight:
w = mg so
w = 166(9.8) so
w = 1600N, rounded to the correct number of sig dig. We use that now in the power equation:
and isolating the unknown:
so
t = 5.3 seconds
A coil of wire with a current flowing thru it becomes a magnet