Answer:
Ф = 239.73 rad
Explanation:
α = 12 + 15×t
W = ∫α×dt
= ∫(12 + 5×t)×dt
= 12×t + 2.5×t^2
then:
Ф = ∫W×dt
= ∫(12×t + 2.5×t^2)dt
= 6×t^2 + 5/6×t^3
therefore the angle at t = 4.88s is:
Ф = 6×(4.88)^2 + 5/6×(4.88)^3
= 239.73 rad
Answer:
The electric current in the wire is 0.8 A
Explanation:
We solve this problem by applying the formula of the magnetic field generated at a distance by a long and straight conductor wire that carries electric current, as follows:

B= Magnetic field due to a straight and long wire that carries current
u= Free space permeability
I= Electrical current passing through the wire
a = Perpendicular distance from the wire to the point where the magnetic field is located
Magnetic Field Calculation
We cleared (I) of the formula (1):
Formula(2)

a =8cm=0.08m

We replace the known information in the formula (2)

I=0.8 A
Answer: The electric current in the wire is 0.8 A
Answer:
<em>Magnetic</em><em> </em><em>compass</em><em> </em><em>helps</em><em> </em><em>to </em><em>identify</em><em> </em><em>direction</em><em> </em><em>in </em><em>this </em><em>way </em><em>,</em><em> </em><em>this </em><em>compass</em><em> </em><em>work </em><em>because</em><em> </em><em>of </em><em>earth</em><em> </em><em>magnetic</em><em> field</em><em> </em><em>and </em><em>show</em><em> </em><em>us </em><em>direction</em><em> </em>
<em> </em><em> </em><em>hope</em><em> it</em><em> helps</em><em> and</em><em> your</em><em> day</em><em> will</em><em> be</em><em> full</em><em> of</em><em> happiness</em><em>. </em>^_^
Answer:
0.68 m
Explanation:
We know that the speed of sound in air is a product of frequency and wavelength. Taking speed of sound in air as 340 m/s
V=frequency*wavelength
Then wavelength is given by 350/500=0.68 m
Therefore, to repeat constructive interference at the listener's ear, a distance of 0.68 m is needed
Answer:
4m/s
Explanation:
May be different considering how long the pole is and how heavy the firefighter is.