In order to calculate the thermal energy, first let's calculate the power, using the formula:

For a voltage V = 9 Volts and a resistance R = 50 ohms, we have:

Now, multiplying the power by the time (in seconds), we can find the energy:

In scientific notation, we have an energy of 7.3 * 10^2 J, therefore the correct option is the fourth one.
Answer:
8.97 Watt
Explanation:
Resistance, R = 20 ohm
Inductance, L = 10 mH
V(t) = 20 Cos (1000 t + 45°)
Compare with the standard equation
V(t) = Vo Cos(ωt + Ф)
Ф = 45°
ω = 1000 rad/s
Vo = 20 V
Inductive reactance, XL = ωL = 1000 x 0.01 = 10 ohm
impedance is Z.


Z = 22.36 ohm



Apparent power is given by
P = Vrms x Irms
P = 14.144 x 0.634
P = 8.97 Watt
Answer: 200 N/m
Explanation:
The Gravitational spring energy(Us) is equal to 1/2kx^2. So we have x as .2 m and Us as 4 N. So 4 N = 1/2 * k * .2^2. So now we solve for K and get 200 N/m.