Answer:
88.3
Explanation:
Emf in a rotating coil is given by rate of change of flux:
E= dФ/dt=(NABcos∅)/ dt
N: number of turns in the coil= 80
A: area of the coil= 0.25×0.40= 0.1
B: magnetic field strength= 1.1
Ф: angle of rotation= 90- 37= 53
dt= 0.06s
E= (80 × 0.4× 0.25×1.10 × cos53)/0.06= 88.3V
Answer:
The time to boil the water is 877 s
Explanation:
The first thing we must do is calculate the external resistance (R) of the circuit, from the description we notice that it is a series circuit, by which the resistors are added
V = i (r + R)
We replace we calculate
r + R = V / i
R = v / i - r
R = 10/12 -0.04
R = 0.793 Ω
We calculate the power supplied
P = V i = I² R
P = 12² 0.793
P = 114 W
This is the power dissipated in the external resistance
We use the relationship, that power is work per unit of time and that work is the variation of energy
P = E / t
t = E / P
t = 100 10³/114
t = 877 s
The time to boil the water is 877 s
Answer:
Explanation:
Given that,
A lady falling has a final velocity of 4m/s
v = 4m/s
Mass of the lady is 60kg.
m = 60kg
Using conservation of energy, the potential energy of the body from the point where the lady is dropping is converted to the final kinetic energy of the lady.
Therefore,
P.E = K.E(final) = ½mv²
P.E = ½ × 60 × 4²
P.E = 480 J.
Answer:
326.25 kWh
Explanation:
Efficiency of a machine is defined as the ratio of useful energy to that of the energy consumed by the machine.
Here, efficiency is given as 87% and the energy consumed by the computer is 375 kWh.
Efficiency, 
Plug in the values of 
and 375 kWh for energy consumed. Solve for useful energy. This gives,
Efficiency, 
Therefore, the useful energy provided by the computer is 326.25 kWh.
Answer
given,
mass of the block = 200 g = 0.2 Kg
Velocity at A = 0 m/s
Velocity at B = 8 m/s
slide to the horizontal distance = 10 m
height of the block be = 4 m
potential energy of the block
P = m g h
P = 0.2 x 9.8 x 4
P =7.84 J
kinetic energy
Work = P - KE
work = 7.84 - 6.14
work = 1.7 J
b) v² = u² + 2 a s
0 = 8² - 2 x a x 10
a = 3.2 m/s²
ma - μ mg = 0
