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
Answer:
h f = Wf + K
where the total energy available is h f, Wf is the work function or the work needed to remove the electron and K is the kinetic energy of the removed electron
If K = zero then hf = Wf
Wf = h f = h c / λ or
λ = h c / Wf = 6.63E-34 * 3.0E8 / (3.7 * 1.6E-19)
λ = 6.63 * 3 / (3.7 * 1.6) E-7 = 3.36E-7
This would be 3360 angstroms or 336 millimicrons
Visible light = 400-700 millimicrons
Heat, like sound, is kinetic energy. Molecules at higher temperatures heave more energy, thus they can vibrate faster. Since the molecules vibrate faster, sound waves can travel more quickly.
So the answer is A.
Answer:
F = MA
Explanation:
OP you didn't give us any examples, but force equals mass times acceleration is Newton's First Law.
Dropping a ball (mass) from the top of a building can show gravity, a form of acceleration.