How roofs are lifted off building in tornado?
1 answer:
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Answer:
v1 = v2
Explanation:
Given:
- The missing figure is (attached).
- The Magnetic Field B1 > B2
Find:
How does the speed v1 of the electron in region 1 compare with the speed v2 in region 2?
Solution:
- From Lorentz Law we know that the Force that acts on the charge particle is the cross product of Magnetic Field Vector ( B1 or B2 ) and the velocity vector (v1 or v1).
- From the attached figure related to this problem we see that the electron velocity or direction of motion is always parallel to the magnetic field B1&B2.
- The law of cross product for parallel vector is 0. Hence, the Lorentz force acting on the electron is also zero.
- Zero Force means no work is done on the particle by the magnetic field, thus, the change in kinetic energy also zero for conservation of energy to hold.
- The initial and final kinetic energies of the electron is same. Hence, we can conclude that v1 = v2.
Answer:
1.64 rad/s
Explanation:
Given,
radius of merry-go-round, r = 1.80 m
mass of merry-go-round, M = 120 Kg
angular speed, ω = 0.350 rev/s
Initial angular speed = 2π x 0.350 = 2.12 rad/s
Mass of child, m = 36.5 Kg
Moment of inertia of the merry-go-round
L= I ω = 349.92 x 2.12 = 769.41 kgm²/s
Child moment of inertia
I₂ = m r^2 = 36.5 x 1.8² = 118.26 kg.m²
Final moment of inertia,
I_f = 349.92+118.26 = 468.18 kg.m²
Final speed =
angular speed of the child is equal to 1.64 rad/s