Answer:
16.8ohms
Explanation:
According to ohm's law which states that the current passing through a metallic conductor at constant temperature is directly proportional to the potential difference across its ends.
Mathematically, V = IRt where;
V is the voltage across the circuit
I is the current
R is the effective resistance
For a series connected circuit, same current but different voltage flows through the resistors.
If the initial current in a circuit is 19.3A,
V = 19.3R... (1)
When additional resistance of 7.4-Ω is added and current drops to 13.4A, our voltage in the circuit becomes;
V = 13.4(7.4+R)... (2)
Note that the initial resistance is added to the additional resistance because they are connected in series.
Equating the two value of the voltages i.e equation 1 and 2 to get the resistance in the original circuit we will have;
19.3R = 13.4(7.4+R)
19.3R = 99.16+13.4R
19.3R-13.4R = 99.16
5.9R = 99.16
R= 99.16/5.9
R = 16.8ohms
The resistance in the original circuit will be 16.8ohms
Answer:
Acceleration = 9 × 10^5 m/s^2 ( deceleration )
Explanation:
From the first equation of motion:
V = u + at
15000 = 30000 + 60a
a = ( 15000-30000)/60
a = 9 × 10^5 m/s^2
Try This Method(substitute your values)
Centripetal force = Mass X Velocity^2/ Radius
<span>F= mv^2/r </span>
<span>so 80.5 X 40^2/200 </span>
<span>=644N</span>
Option ( c ) is correct.
Using the formula for power

P= power
i= current= 0.4 A
R= resistance= 30 ohm
so power= (0.4)² (30)
Power=4.8 W