Answer:
1.25 kgm²/sec
Explanation:
Disk inertia, Jd =
Jd = 1/2 * 3.7 * 0.40² = 0.2960 kgm²
Disk angular speed =
ωd = 0.1047 * 30 = 3.1416 rad/sec
Hollow cylinder inertia =
Jc = 3.7 * 0.40² = 0.592 kgm²
Initial Kinetic Energy of the disk
Ekd = 1/2 * Jd * ωd²
Ekd = 0.148 * 9.87
Ekd = 1.4607 joule
Ekd = (Jc + 1/2*Jd) * ω²
Final angular speed =
ω² = Ekd/(Jc+1/2*Jd)
ω² = 1.4607/(0.592+0.148)
ω² = 1.4607/0.74
ω² = 1.974
ω = √1.974
ω = 1.405 rad/sec
Final angular momentum =
L = (Jd+Jc) * ω
L = 0.888 * 1.405
L = 1.25 kgm²/sec
In a particle accelerator a positron (C= +1.6 x 10-19) travels through a perpendicular magnet field with a magnitude
of 3.1 x 10-2 T. At what speed must the positron travel in order for it to experience a force of 4.75 x 10-14 N?
28. An alpha particle (2 protons and 2 neutrons) experiences a downward force of 2.9 x 10-14 N while traveling in a
magnetic field with a strength of 5.1 x 10-19 T pointing to the north. Find the speed of the particle and the direction
it must be traveling in.
29. Find the length of a wire if it experiences a .63N force when it travels through a magnetic field with a strength of
0.85T whilst carrying 5.0 amps of current.
30. A coil with 462 turns of wire, a total resistance of 36Ω , and a cross-sectional area of 0.25 m2
is positioned with its
plane perpendicular to the field of a powerful electromagnet. What average current is induced in the coil during the 0.37s
that the magnetic field drops from 3.1 T to 0.0 T?
31. A step-up transformer has a potential difference across the primary of 28 V and a potential difference across the
secondary of 3.0 × 104
V. There are 28 turns in the primary coil. How many turns are in the secondary?
32. A step-up transformer is used to create a potential difference of 1.6872 × 105
V across the secondary. The potentia
Answer:
The amount of heat transfer is 21,000J .
Explanation:
The equation form of thermodynamics is,
ΔQ=ΔU+W
Here, ΔQ is the heat transferred, ΔU is the change in internal energy, and W is the work done.
Substitute 0 J for W and 0 J for ΔU
ΔQ = 0J+0J
ΔQ = 0J
The change in internal energy is equal to zero because the temperature changes of the house didn’t change. The work done is zero because the volume did not change
The heat transfer is,
ΔQ=Q (in
) −Q (out
)
Substitute 19000 J + 2000 J for Q(in) and 0 J for Q(out)
ΔQ=(19000J+2000J)−(0J)
=21,000J
Thus, the amount of heat transfer is 21,000J .
Answer: La diferencia es el peso (o la masa), siendo que el cubo de hierro es el mas pesado, después viene el de madera y después el de icopor.
Explanation:
Ok, los 3 cubos tienen el mismo tamaño, lo que implica que tienen el mismo volumen.
Ahora es útil recordar la relación:
Densidad = masa/volumen.
Masa = densidad*volumen.
Nosotros sabemos que la densidad del hierro es mas grande que la de la madera, y la densidad de la madera es mas grande que la del icopor.
Entonces, por la relación anterior, y sabiendo que todos los cubos tienen el mismo volumen, podemos reconocer que el cubo de hierro tiene mayor masa, después viene el de madera y después viene el de icopor.
Y sabiendo que:
masa*gravedad = peso
podemos saber que el cubo mas pesado es el de hierro, después el de madera y después el de icopor.
Además de esta diferencia, también hay otras que no dependen tanto del tamaño del objeto, como pueden ser las capacidades caloríficas, el como reaccionan a campos eléctricos y cosas así que son triviales, pues son diferentes para casi todos los materiales.
F= Force
M=Mass
A= acceleration
F=N
Mass= in grams or kilo grams (mostly kg)
A= m/s
