An ice skater performs a pirouette (a fast spin) by pulling in his outstretched arms close to his body. What happens to his rota
1 answer:
Answer:
rotational kinetic energy increases
Explanation:
when an ice skater pulls his arms closer to his body there is no rotational torque because we know that torque = F×R here R is the distance and when arms are closer to body distance is very less so there will be no torque and so angular momentum is conserved but moment of inertia is also decreases and we know that rotational kinetic energy =
where L= angular momentum
I = moment of inertia
as moment of inertia decreases and angular momentum is conserved so using the formula rotational kinetic energy increases
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Explanation:
We will calculate the gravitational potential energy as follows.
=
= 1164000 J
or, = 1164 kJ (as 1 kJ = 1000 J)
Now, we will calculate the change in potential energy as follows.
=
=
= -873000 J
or, = -873 kJ
Thus, we can conclude that change in gravitational potential energy is -873 kJ.