Answer:
155.5 rev/min
Explanation:
First, we will calculate the initial moment of inertia I_o. We will consider the ice skater as a rod rotating around its axis. Then, we calculate the final moment of inertia I_f. In this occasion we consider the arms as a rod of length L that is horizontally positioned, L so that the length of an arm is L/2. We will call M_1 the mass that remains close to the rotation axis (90 percent) and M_2 the mass located at the arms (10 percent). Finally, we write the equation for the conservation of angular momentum and we solve for ω_f.
I_o=MR^2/2
=(45)(0.15)^2/2
=0.5 kgm^2
M_1=(0.9)(45)
=40.5 kg
M_2=(0.1)(45)
=4.5 kg
I_f=M_1*R^2/2+M_2*L^2/12
=1.1 kg m^2
I_f*ω_f=I_o*ω_o
ω_f = I_o*ω_o/ I_f
=155.5 rev/min
Answer:
Frequencia = 1.25 Hz
Explanation:
<u>Dados los siguientes datos;</u>
- Velocidad = 50 m/s
- Longitud de onda = 40 metros
Para encontrar la frecuencia de la onda;
Matemáticamente, la velocidad de una onda viene dada por la fórmula;
Haciendo de la frecuencia el tema de la fórmula, tenemos;
Sustituyendo en la fórmula, tenemos;
<em>Frequencia = 1.25 Hz</em>
Answer:
a) t =12[s]; b) x = 348[m]
Explanation:
We can solve this problem using the following kinematics equations:
a)
where:
vf = final velocity = 12 [m/s]
vo= initial velocity = 6 [m/s]
a = acceleration = 0.5[m/s^2]
t = time [s]
Now clearing the time t, we have:
b)
We can calculate the displacement for the first 12 [s] then using the equation for the constant velocity we can calculate the other displacement for the 20[s].
The we can calculate the second displacement for the constant velocity:
x = x1 + x2
x = 108 + 240
x = 348[m]
Answer:
the two pink/purple in the first box with the green ones and blue and grey in the second box
Answer:
Because electromagnetic waves can travel through empty space
Explanation:
The energy that is emitted from the sun is transferred to the earth in the form of radioactive waves. These waves are originated due to the vibration between the electric and magnetic fields. As this energy reaches the earth, it warms the earth's atmosphere, resulting in the transfer of heat energy in three possible ways namely the conduction, convection, and radiation.
This electromagnetic waves do not require any matter for the transmission of energy, and can easily travel in empty space from the core of the sun to the earth and other nearby planets. Whereas other types of waves cannot travel in space, so it is transferred in the form of electromagnetic waves only.