Answer:
Explanation:
Momentum conservation

Kinetic energy conservation

Solve the system
Answer:
v = 5.24[m/s]
Explanation:
Este problema se puede resolver por medio del principio de la conservación de la energía, donde la energía potencial es igual a la energía cinética. Es decir a medida que el carrito desciende su energía potencial disminuye, pero su energía cinética aumenta.

Donde:

Ahora reemplazando:
![\frac{1}{2} *m*v^{2}=m*g*h\\\\0.5*v^{2}=9.81*1.4\\v=\sqrt{\frac{9.81*1.4}{0.5} } \\\\v=5.24[m/s]](https://tex.z-dn.net/?f=%5Cfrac%7B1%7D%7B2%7D%20%2Am%2Av%5E%7B2%7D%3Dm%2Ag%2Ah%5C%5C%5C%5C0.5%2Av%5E%7B2%7D%3D9.81%2A1.4%5C%5Cv%3D%5Csqrt%7B%5Cfrac%7B9.81%2A1.4%7D%7B0.5%7D%20%7D%20%20%20%5C%5C%5C%5Cv%3D5.24%5Bm%2Fs%5D)
Answer:
0.5 A
Explanation:
N = 20, A = 50 cm^2 = 50 x 10^-4 m^2, dB = 6 - 2 = 4 T, dt = 2 s, R = 0.4 ohm
The induced emf is given by
e = - N dФ/dt
Where, dФ/dt is the rate of change of magnetic flux.
Ф = B A
dФ/dt = A dB/dt
so,
e = 20 x 50 x 10^-4 x 4 / 2 = 0.2 V
negative sign shows the direction of magnetic field.
induced current, i = induced emf / resistance = 0.2 / 0.4 = 0.5 A
I think that the answer is C)