Answer:
The moment of inertia decreased by a factor of 4
Explanation:
Given;
initial angular velocity of the ice skater, ω₁ = 2.5 rev/s
final angular velocity of the ice skater, ω₂ = 10.0 rev/s
During this process we assume that angular momentum is conserved;
I₁ω₁ = I₂ω₂
Where;
I₁ is the initial moment of inertia
I₂ is the final moment of inertia
Therefore, the moment of inertia decreased by a factor of 4
As we know that reaction time will be
so the distance moved by car in reaction time
now the distance remain after that from intersection point is given by
So our distance from the intersection will be 100 m when we apply brakes
now this distance should be covered till the car will stop
so here we will have
now from kinematics equation we will have
so the acceleration required by brakes is -2 m/s/s
Now total time taken to stop the car after applying brakes will be given as
total time to stop the car is given as