Answer:
4 A
Explanation:
V = IR, where V=voltage, I=current, R=resistance. This is Ohm's Law. (remember that for units V = volts, Ω = ohms, A = amperes.)
V = IR
12 V = I * 3 Ω
12/3 = I
<u>I = 4 A</u>
Answer:
Approximately 
.
Explanation:
The average speed of a vehicle is calculated as:
.
In this question, the total distance is 
.
The unit of the speeds in this question is meters per second, while the unit of distance is kilometers. Convert the unit of distance to meters:
.
.
Time required for the first part of this trip:
.
Time required for the second part of this trip:
.
The time required for the entire trip would be approximately 
.
Calculate the average speed of this plane:
.
Answer:
P= 390 W
Explanation:
In physics, power is the rate of doing work or of transferring heat, i.e. the amount of energy transferred or converted per unit time. Work is a force F applied over a distance x. Matemathicaly it means
P = dW/dt ≈ d(F * x)/dt = xdF/dt + Fdx/dt. If force is constant dF/dt=0 so P=F dx/dt = P*v, where v is velocity, the rate of distance per unit time.
We have force and velocity. Newton is unit of Kg*m/s2, hence
P= 150 kgm/s2 * 2.6 m/s =390 Kgm2/s3 = 390 W, where W is Watts and is an unit of power
