Answer:
Option B, to establish the reference polarity for induced voltages
Explanation:
Dot basically indicates the polarity of the electrical windings. Currents entering and leaving the same dotted ends will produce magnetic flux in same direction while the current entering at one dotted end and leaving at another dotted end will produce opposing magnetic flux.
Thus it is clear that dot represents the terminals having same phases of induced AC voltages so that only one winding is loaded at a time.
Hence, option B is correct
The disk's average angular speed during those 5 seconds was
(1/2) (100 + 300) rad/s = 200 rad/sec
Spinning for 5 sec at an average angular speed of 200 rad/s, the disk turned
(200 rad/s) x (5 s) = <em>1,000 radians</em>
(That's 500/pi revolutions = roughly 159.2 revolutions.)
Explanation:
Given that,
Weight of the friend, W = 600 N
When the friend sits on the metal frame it bends downward 4 cm, we can say that the compression in the it is 4 cm or 0.04 m
To find,
Spring constant for this chair or k
Solve :
The weight of an object is equal to the force exerted by the gravitational force, F = 600 N
According to Hooke's law, the force exerted by the spring is given by :
F = kx
k is the spring constant


k = 15000 N/m
Therefore, the spring constant of the spring is 15000 N/m.
Answer:
a) 250 N/m
b) 22.4 rad/s , 3.6 Hz , 0.28 sec
c) 0.3125 J
Explanation:
a)
F = force applied on the spring = 7.50 N
x = stretch of the spring from relaxed length when force "F" is applied = 3 cm = 0.03 m
k = spring constant of the spring
Since the force applied causes the spring to stretch
F = k x
7.50 = k (0.03)
k = 250 N/m
b)
m = mass of the particle attached to the spring = 0.500 kg
Angular frequency of motion is given as


= 22.4 rad/s
= frequency
Angular frequency is also given as
= 2 π
22.4 = 2 (3.14) f
= 3.6 Hz
= Time period
Time period is given as


= 0.28 sec
c)
A = amplitude of motion = 5 cm = 0.05 m
Total energy of the spring-block system is given as
U = (0.5) k A²
U = (0.5) (250) (0.05)²
U = 0.3125 J
When all parts of a circuit are composed of conducting materials,
then it's possible for current to flow in the circuit, and we say that
the circuit is "closed".