Answer:
114.44 J
Explanation:
From Hook's Law,
F = ke................. Equation 1
Where F = Force required to stretch the spring, k = spring constant, e = extension.
make k the subject of the equation
k = F/e.............. Equation 2
Given: F = 10 lb = (10×4.45) N = 44.5 N, e = 4 in = (4×0.254) = 1.016 m.
Substitute into equation 2
k = 44.5/1.016
k = 43.799 N/m
Work done in stretching the 9 in beyond its natural length
W = 1/2ke²................. Equation 3
Given: e = 9 in = (9×0.254) = 2.286 m, k = 43.799 N/m
Substitute into equation 3
W = 1/2×43.799×2.286²
W = 114.44 J
Answer:
In 5 years or so, the sun will be awash in sunspots and more prone to violent bursts of magnetic activity.
Explanation
once the magnetic field weakens the area and cold plasma enters the area of the sunspot
Answer: B.
Capacitors prevent current from moving through a circuit
Explanation:
If a direct voltage is applied on the capacitor, no conduction current flows through the capacitor if its insulating medium is perfect insulator. This is due to the fact that there are no free charge carriers in such medium. Basically the real insulator contains very few charge carriers and therefore a very small leakage current passes in the capacitor depending on the conductivity of the insulator.
If an alternating voltage is applied on the capacitor, a displacement current passes through the capacitor irrespective of the insulating medium. This current is termed also the capacitive current. It flows because of changing electric displacement with time.
Voltage - V = IR : v= voltage i= current r= resistance
Im not understanding the question but this is true
