Assume that the motor has accelerated the wheel up to an angular velocity ï1 with angular acceleration î± in time t1. at this point, the motor is turned off and a brake is applied that decelerates the wheel with a constant angular acceleration of â5î±. find t2, the time it will take the wheel to stop after the brake is applied (that is, the time for the wheel to reach zero angular velocity). express your answer in terms of some or all of the following: ï1, î±, and t1.

t₂ = t₁ / 5

Explanation:

Rotational kinematics using:  ωf = ωi + αt

Starting from rest and speeding up:

ω₁ = 0 + αt₁  ..  Eq1

Starting from ω₁ and slowing to a stop:

0 = ω₁ - 5αt₂  

Substituting for ω₁ from Eq 1

0 = αt₁ - 5αt₂  

5αt₂ = αt₁  

5t₂ = t₁

t₂ = t₁ / 5

as we know our atmosphere or air have different levels. every level has other gasses, and every gas has another permeability. when the light comes from lower permeability to higher permeability, it changes its direction. so that means that when the light comes from the moon to the earth, it changes it's direction many more times. it basically means that the shape of the light part of the moon is changed on the earth.

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a sonic boom is a loud boom that breaks the sound barrier

explanation: