The beginning momentum of the object is zero
Explanation:
The momentum of an object is given by:
where
m is the mass of the object
v is its velocity
For the object in this problem, we have:
m = 3.0 kg is its mass
v = 0, because it is initially at rest, so its initial velocity is zero
Therefore, the initial momentum of the object is
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Answer:
B.)Angular momentum is always conserved
Explanation:
Angular momentum is given by:
where
m is the mass of the object
v is its speed
r is the distance between the object and the centre of its circular trajectory
In absence of external torques, angular momentum is always conserved. That means that for the spinning star, if its radius r decreases (because it shrinks), in order for L (the angular momentum) to be conserved, the speed (v) must increases, therefore the spinning star speeds up.
So, the correct choice is
B.)Angular momentum is always conserved