To solve this problem it is necessary to apply the definition given in Faraday's law in a solenoid for which it is noted that


Where,
N = Number of loops
A = Cross sectional Area
B = Magnetic Field



Therefore the correct answer is A.
Answer choice d is correct
It can help determine substances that appear similar but react differently under the same circumstances.
Answer:
a) Ws = 2.548 J
b) Wf = 1.153 J
c) v = 1.923 m / s
Explanation:
a) The work done by the spring force
Ws = ½ * k * x²
Ws = ½ * 260 N/m *0.14² m
Ws = 2.548J
b) The increase in thermal energy can by find using
Et = Wf
Wf = µ * m *g * x
Wf = 0.42 * 2.0 kg *9.8 m/s² * 0.14m
Wf = 1.153 J
c) The speed just as the block reaches can by fin using
EK = Ws + Et
Ek = ( 2.548 + 1.153 ) J = 3.7 J
Ek = ½ * m * v²
v² = 2* Ek / m
v = √[2 * 3.7 J / 2.0 kg]
v = 1.923 m / s