Cho mạch điện như hình vẽ: Biết: R1 = 15, R2 = R3 = R4 = 20; RA = 0; ampe kế chỉ 2A.
Tính cường độ dòng điện qua các điện trở R1, R2, R3, R4.

Along wire carrying a 4.2 a current perpendicular to the xy-plane intersects the x-axis at x=−1.7cm. a second, parallel wire carrying a 3.0 a current intersects the x-axis at x=+1.7cm. part a at what point on the x-axis is the magnetic field zero if the two currents are in the same direction? express your answer to two significant figures and include the appropriate units.

In which situation is the acceleration of a car negative? question 5 options: a)the velocity of a car was 75 km/hr over 4 hours. b)the velocity of a car reduced from 50 km/hr over one minute. c)the velocity of a car increased from 40 km.h to 75 km/h over 15 minutes. d)the velocity of a car was 45 km/hr at 2: 00pm and at 4: 00pm its velocity was 85 km/ht.

Acar going 10 m/s starts accelerating at a rate of 3 m/s2 for 4 seconds calculate the final velocity of the car