Answer:
F = 274.68[N]
Explanation:
The gravitational force is equal to the weight of a body, or this case that of a person. Weight can be calculated by means of the product of mass by gravitational acceleration. In this way we have the following equation:

where:
F = force or weight [N]
m = mass = 28 [kg]
g = gravity acceleration = 9.81 [m/s²]
Now replacing:
![F=28*9.81\\F=274.68[N]](https://tex.z-dn.net/?f=F%3D28%2A9.81%5C%5CF%3D274.68%5BN%5D)
Answer:
The coil radius of other generator is 5.15 cm
Explanation:
Consider the equation for induced emf in a generator coil:
EMF = NBAω Sin(ωt)
where,
N = No. of turns in coil
B = magnetic field
A = Cross-sectional area of coil = π r²
ω = angular velocity
t = time
It is given that for both the coils magnetic field, no. of turn and frequency is same. Since, the frequency is same, therefore, the angular velocity, will also be same. As, ω = 2πft.
Therefore, EMF for both coils or generators will be:
EMF₁ = NBπr₁²ω Sin(ωt)
EMF₂ = NBπr₂²ω Sin(ωt)
dividing both the equations:
EMF₁/EMF₂ = (r₁/r₂)²
r₂ = r₁ √(EMF₂/EMF₁)
where,
EMF₁ = 1.8 V
EMF₂ = 3.9 V
r₁ = 3.5 cm
r₂ = ?
Therefore,
r₂ = (3.5 cm)√(3.9 V/1.8 V)
<u>r₂ = 5.15 cm</u>
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Answer:
2.145×10^-10 V or 0.2145nV
Explanation:
From hf=eV
h= Plank's constant = 6.6×10^-34JS
f= frequency of the electromagnetic wave = 5.2×10^4 Hz
e= electronic charge= 1.6×10^-19 C
V= voltage
V= hf/e
V= 6.6×10^-34JS × 5.2×10^4 Hz/ 1.6×10^-19 C
V= 2.145×10^-10 V or 0.2145nV
Therefore the voltage created is 2.145×10^-10 V or 0.2145nV
Answer:
T = 188.5 s, correct is C
Explanation:
This problem must be worked on using conservation of angular momentum. We define the system as formed by the fan and the paper, as the system is isolated, the moment is conserved
initial instant. Before the crash
L₀ = r m v₀ + I₀ w₀
the angular speed of the fan is zero w₀ = 0
final instant. After the crash
L_f = I₀ w + m r v
L₀ = L_f
m r v₀ = I₀ w + m r v
angular and linear velocity are related
v = r w
w = v / r
m r v₀ = I₀ v / r + m r v
m r v₀ = (I₀ / r + mr) v
v = 
let's calculate
v = 
v = 
v = 0.02 m / s
To calculate the time of a complete revolution we can use the kinematics relations of uniform motion
v = x / T
T = x / v
the distance of a circle with radius r = 0.6 m
x = 2π r
we substitute
T = 2π r / v
let's calculate
T = 2π 0.6/0.02
T = 188.5 s
reduce
t = 188.5 s ( 1 min/60 s) = 3.13 min
correct is C