The answer is electricity
Answer:
Explanation:
a) Energy stored in spring = 1/2 k x² = .5 x k 0.1²
500 = 5 x 10⁻³ k ,
k = (500/5) x 10³ = 10⁵ N/m
b )
k = 4.5 x 10¹ = 45 N/m
Stored energy = 1/2 k x² = .5 x 45 x 8² x 10⁻⁴ =1440 x 10⁻⁴ J
This energy gets dissipated by friction .
work done by friction = μ mg d
d is the distance traveled under friction
so 1440 x 10⁻⁴ = μ x 3 x 9.8 x 2
μ = 245 x 10⁻⁴ or 0.00245 which appears to be very small. .
Answer:
The tangential velocity of a rotating object is:
v = r*w
where r is the radius, and w is the angular velocity.
w = 2*pi*f
where f is the frequency.
We know that the record plater does 11 revolutions in 20 seconds, then it does:
11 rev/20s = 0.55 rev/s = f
then we have:
w = 2*pi*0.55 s^-1 = 2*3.14*0.55 s^-1 = 3.454 s^-1
The radius of a record player is really variable, it is around 10 inches, so i will use r = 10in, which is the rotating part of the record player.
then the tangential velocity is:
v = 10in*3.454 s^-1 = 34.54 in/s
I think the correct answer would be B. The process of elastic rebound is being shown by the student. It is a theory that is used to explain earthquakes. It focuses on how energy is being spread in times of earthquakes. As the rocks on the fault experiences shift and force, these rocks would be accumulating energy causing it to deform reaching the internal strength and eventually exceeding it. At that moment, a rapid motion would happen along the fault, which releases the energy, then the rocks would go back to its original shape or the undeformed state. This theory is the first theory that sufficiently was able to explain earthquakes.
