If a football is thrown from rest with an acceleration of 8.5 m/s2, and had an final
1 answer:
Answer:
t = 2.94 seconds
Explanation:
Given that,
The initial velocity of the football, u = 0
The final velocity of the football, u = 25 m/s
Acceleration, a = 8.5 m/s²
We need to find the time for which the football is accelerating. Let the time is t. We know that,
So, the football is accelerating for 2.94 seconds.
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Answer:
the moment of inertia with the arms extended is Io and when the arms are lowered the moment
I₀/I > 1 ⇒ w > w₀
Explanation:
The angular momentum is conserved if the external torques in the system are zero, this is achieved because the friction with the ice is very small,
L₀ = L_f
I₀ w₀ = I w
w = w₀
where we see that the angular velocity changes according to the relation of the angular moments, if we approximate the body as a cylinder with two point charges, weight of the arms
I₀ = I_cylinder + 2 m r²
where r is the distance from the center of mass of the arms to the axis of rotation, the moment of inertia of the cylinder does not change, therefore changing the distance of the arms changes the moment of inertia.
If we say that the moment of inertia with the arms extended is Io and when the arms are lowered the moment will be
I <I₀
I₀/I > 1 ⇒ w > w₀
therefore the angular velocity (rotations) must increase
in this way the skater can adjust his spin speed to the musician.