Answer:
0.4rad/s²
Explanation:
Angular acceleration is the time rate of change of angular velocity . In SI units, it is measured in radians per second squared (rad/s²)
w1 = 4rad/s, w2 =2rad/s, t = 5sec, r = 0.30m
a = ∆w/t
a = (w2 - w1)/t
a = (2 - 4)/5 = -2/5 =
a = - 0.4rad/s²
The -ve sign indicates a deceleration in the motion
Good luck
Back emf is 85.9 V.
<u>Explanation:</u>
Given-
Resistance, R = 3.75Ω
Current, I = 9.1 A
Supply Voltage, V = 120 V
Back emf = ?
Assumption - There is no effects of inductance.
A motor will have a back emf that opposes the supply voltage, as the motor speeds up the back emf increases and has the effect that the difference between the supply voltage and the back emf is what causes the current to flow through the armature resistance.
So if 9.1 A flows through the resistance of 3.75Ω then by Ohms law,
The voltage across the resistance would be
v = I x R
= 9.1 x 3.75
= 34.125 volts
We know,
supply voltage = back emf + voltage across the resistance
By plugging in the values,
120 V = back emf + 34.125 V
Back emf = 120 - 34.125
= 85.9 Volts
Therefore, back emf is 85.9 V.
Answer:
d = 1.047 mm
Explanation:
given,
diameter of the wire = 2.0-cm
length of solenoid = 15 cm = 0.15
Current in the wire = I = 2.5 A
magnetic field = B = 3.0 mT
Magnetic field inside the solenoid


N x d = l




d = 1.047 x 10⁻³ m
d = 1.047 mm
diameter of the wire is d = 1.047 mm
20 joule is your answer
Answer:
here
mass m =100kg
distance d=50m
acceleration due to gravity a =10m/s²
work =force×displacement
= ma/d=100×10/50=20joule
I believe the answer is D.