Answer:
C. 72
Explanation:
Transformer: A transformer is an electromagnetic device that uses the property of mutual inductance to change the voltage of alternating supply.
In a ideal transformer,
Vs/Vp = Ns/Np ............................................. Equation 1
Where Vp = primary voltage, Vs = secondary voltage, Ns = Secondary turn, Np = primary turn.
Making Ns the subject of the equation,
Ns =(Vs/Vp)Np .......................................... Equation 2
Given: Vs = 24 V, Vp = 115 V, Np = 345.
Substitute into equation 2
Ns = (24/115)345
Ns = 72 turns.
Thus the number of turns in the secondary = 72 turns.
The right option is C. 72
<span>Heat energy is transferred from warmer objects to cooler objects.
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(a)
KE = m v^2 / 2 = (1200 kg)(20 m/s)^2 / 2 = 240,000 J
(b)
The energy is entirely dissipated by the force of friction in the brake system.
(c)
W = delta KE = KEf - KEi = (0 - 240,000) J = -240,000 J
(d)
Fd = delta KE
F = (delta KE) / d = (-240,000 J) / (50 m) = -4800 N
The magnitude of the friction force is 4800 N.
Explanation:
F=m(v-u)/t
F=2N
m=2kg
t=2s
2=2(v-u)/2
cross multiply
2*2=2(v-u)
4=2(v-u)
4/2=v-u
v-u=2m/s
v-u is the change is velocity.
