Um motor de indução trifásico de 220 V é conectado a rede elétrica por meio de um circuito trifásico com cabos de resistência total 0,25Ω. A corrente de regime desse motor é igual a 8 A. Se a corrente para partida direta for igual a 8 vezes o valor da corrente de regime, utilizando-se o método de partida estrela-triângulo qual será a tensão nos terminais desse motor na partida? A) 216,7 V
B) 204,8 V
C) 214,7 V
D) 218,3V
E) 220V constante porque é a tensão da rede.

Abrake has a normal braking torque of 2.8 kip in and heat-dissipating cast-iron surfaces whose mass is 40 lbm. suppose a load is brought to rest in 8.0 s from an initial angular speed of 1600 rev/min using the normal braking torque; estimate the temperature rise of the heat dissipating surfaces.

Afour cylinder four-stroke in-line engine has a stroke of 160mm, connecting rod length of 150mm, a reciprocating mass of 3kg and its firing order is 1-3-4-2. the spacing between cylinders is 100mm. i. show that the engine is in balance with regard to the primary inertia forces and primary 3. a and secondary inertia couples. li determine the out of balance secondary inertia force ii. propose ways of balancing this out of balance force and discuss the challenges that will arise

Prove the equivalence between the two statements of the 2nd law of thermodynamics (i.e., a violation of one statement leads to the violatio the other statement)